Patent Publication Number: US-10786426-B2

Title: Dual plumbing system for a hot tub or spa

Description:
FIELD 
     This disclosure relates to systems and methods for hot tub, swim spa and personal therapy unit plumbing systems. More specifically, the disclosed embodiments relate to improved methods for simultaneously providing water and air to jets in a hot tub or spa. 
     BACKGROUND 
     A hot tub or spa is a pool of heated water typically sized to provide space for between one and ten people. Hot tubs and spas are often used for relaxation, various forms of therapy (including hydrotherapy and/or aromatherapy), pleasure, massage, training, and/or rehab (for example, in the case of a swim spa). Hot tubs and spas may be located either indoors or outdoors. Hot tubs are often used for social gatherings and/or for individual use. In addition, hot tubs are known to have a variety of health benefits. Hot tubs and spas can come in a wide variety of shapes, sizes, colors, and styles and may include a variety of additional accessories from filters to lights to built-in audio. In many cases, external portions of the hot tub and/or the frame may be decorated. 
     Hot tubs use jets to deliver a combination of water and air to the pool of water contained within the hot tub shell. In many cases, the jets may be used for massage purposes as well as circulating the water. The jets also provide fresh, heated water to the hot tub shell after cycling the water through appropriate heating and filtering systems. A plumbing system separately transports water and/or air from respective sources to the jets which may be located in a variety of places throughout the hot tub shell. The hot tub shell is supported by a hot tub frame which may also serve to contain and protect the plumbing system, as well as providing a structure for applying a decorative exterior. 
     In known methods, air and water are delivered to a given jet by separate tubes and associated system components. A typical hot tub may have approximately 45 jets, though a large hot tub may have many more, potentially more than 100. This can result in a large number of separate tubes which must be installed by hand and contained between the hot tub frame and the hot tub shell. This is a highly complicated process with many steps and involves an extraordinary amount of labor. Accordingly, there is a need for hot tub plumbing systems that simplify the delivery of air and water to the jets, and reduce the labor involved in assembling the hot tub. 
     SUMMARY 
     The plumbing system of the present teachings reduces the amount of labor during installation by significantly decreasing the number of tubes, connections and associated fittings used. This decrease is accomplished by using dual extrusion tubing which delivers air and water simultaneously. Benefits of using dual extrusion tubing may include halving the amount of labor involved in installing the plumbing system in a hot tub as well as decreasing the likelihood of mistakes. Furthermore, dual extrusion tubing can be used in conjunction with specialized manifolds that simplify how air and water are routed to the hot tub jets. Additionally, the systems and methods of installing a plumbing system according to the present teachings simplifies installation by using a “press-and-click” assembly. Benefits of this method of assembly may include a further reduction in labor as well as a reduction in the amount of glue and adhesive used. 
     The present disclosure provides systems, apparatuses, and methods relating to a hot tub plumbing system wherein one portion of the tubing (for example, one passage of a length of dual extrusion tubing) carries a water stream and a second portion carries an air stream. In some embodiments, a hot tub plumbing system may include a “press-and-click” method of assembly and wherein two components may be coupled together when aligned by applying axial compressive forces to overcome a spring bias or other resistive force, after which the components are locked together and O-rings ensure a seal. In some cases, components of the plumbing system can thereby be joined in a water tight manner without the use of glue or primer. The reduction or elimination of glue and primer is significant in many forms. Manual application can be inconsistent, which can lead to failures of the joint that are difficult and costly to repair. Furthermore, glue and primer contain volatile organic compounds that can pose environmental and human health issues. 
     In some embodiments, a jet assembly may include a jet insert, a jet body, and a jet back; wherein the jet back may be configured to be separately coupled to the tubing and then “snapped” onto the jet body according to the “press-and-click” method. In some embodiments, a manifold may be used which can simultaneously provide both air and water streams to the length and/or lengths of tubing and which is configured to couple together, via the “press-and-click” method, with other manifolds to form a multi-port manifold and/or with an end cap to end the flow of water and air. 
     In some examples, a hot tub jet assembly comprises a jet back including a first hollow protrusion configured to receive a stream of water and a second hollow protrusion adjacent the first hollow protrusion and configured to receive a stream of air; and a jet body configured to receive the streams of water and air from the jet back, to merge the streams of water and air together to form a mixed stream of air and water, and to provide the mixed stream of air and water from an outlet; wherein the jet back includes a resilient ring configured to engage one or more hooks disposed on the jet body. 
     In some examples, a hot tub plumbing system comprises a manifold assembly configured to receive separate air and water supply streams and to direct those streams into a water egress port and an air egress port, wherein the air egress port is substantially parallel to and adjacent to the water egress port; a dual extrusion tube including a first tubular portion configured to couple to the water egress port and a second tubular portion configured to couple to the air egress port; a jet back including a pair of adjacent parallel hollow protrusions each configured to receive one of the streams of air and water from a respective one of the tubular portions of the dual extrusion tube; and a jet body configured to receive the streams of air and water from the jet back, to merge the streams of air and water together to form a mixed stream of air and water, and to provide the mixed stream of air and water from an outlet; wherein the jet back includes a resilient member extending from a first end of the jet back and configured to engage one or more projections extending from the jet body. 
     In some examples, a hot tub plumbing system comprises a manifold configured to channel an air stream into an air egress port and to channel a water stream into a water egress port; a dual extrusion tube including a first hollow portion configured to couple to the water egress port and a second hollow portion configured to couple to the air egress port; and a jet back including: a first hollow protrusion configured to receive the water stream from the first hollow portion of the dual extrusion tube; a second hollow protrusion configured to receive the air stream from the second hollow portion of the dual extrusion tube; and a spring-biased ring spaced from a first end of the jet back. 
     Features, functions, and advantages may be achieved independently in various embodiments of the present disclosure, or may be combined in yet other embodiments, further details of which can be seen with reference to the following description and drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  depicts a perspective view of portions of a prior art hot tub plumbing system. 
         FIG. 2  depicts a perspective view of portions of a hot tub plumbing system, according to aspects of the present teachings. 
         FIG. 3  is a block diagram of an exemplary hot tub plumbing system, according to aspects of the present teachings. 
         FIG. 4  is a block diagram of an exemplary jet assembly, according to aspects of the present teachings. 
         FIG. 5  is an exploded sectional view of a jet assembly, according to aspects of the present teachings. 
         FIG. 6  is a partially exploded isometric view of the jet assembly of  FIG. 5 . 
         FIG. 7  is an isometric view of the jet assembly of  FIG. 5 , showing the jet assembly in an assembled state. 
         FIG. 8  is a sectional view of the jet assembly of  FIG. 5 , showing the jet assembly in an assembled state. 
         FIG. 9  is an isometric view of a jet back portion of the jet assembly of  FIG. 5 . 
         FIG. 10  is an isometric view of a nozzle portion of the jet assembly of  FIG. 5 . 
         FIG. 11  is another isometric view of the nozzle portion shown in  FIG. 10 . 
         FIG. 12  is an isometric view of a nozzle portion installed in a jet body portion of the jet assembly of  FIG. 5 . 
         FIG. 13  is an isometric view of the jet body portion shown in  FIG. 12 . 
         FIG. 14  is an isometric view of another embodiment of a jet body that can be used as part of a jet assembly, according to aspects of the present teachings. 
         FIG. 15  is a sectional elevational view of the jet body of  FIG. 14 . 
         FIG. 16  is an isometric view of yet another embodiment of a jet body that can be used as part of a jet assembly, according to aspects of the present teachings. 
         FIG. 17  is a sectional elevational view of the jet body of  FIG. 16 . 
         FIG. 18  is an isometric view of still another embodiment of a jet body that can be used as part of a jet assembly, according to aspects of the present teachings. 
         FIG. 19  is a sectional elevational view of the jet body of  FIG. 18 . 
         FIG. 20  is an exploded isometric view of another embodiment of a jet assembly, according to aspects of the present teachings. 
         FIG. 21  is an isometric view of a jet back portion of the jet assembly of  FIG. 20 . 
         FIG. 22  is a sectional view of yet another embodiment of a jet assembly, according to aspects of the present teachings. 
         FIG. 23  is an exploded sectional view of still another embodiment of a jet assembly, according to aspects of the present teachings. 
         FIG. 24  is a partially exploded isometric view of the jet assembly of  FIG. 23 , showing the jet assembly in a partially assembled state. 
         FIG. 25  is an isometric view of the jet assembly of  FIG. 23 , showing the jet assembly in an assembled state. 
         FIG. 26  is a sectional view of the jet assembly of  FIG. 23  in an assembled state. 
         FIG. 27  is an isometric view of a jet back portion of the jet assembly of  FIG. 23 . 
         FIG. 28  is a partially exploded isometric view of yet another jet assembly, according to aspects of the present teachings. 
         FIG. 29  is an isometric view of a jet back portion of the jet assembly of  FIG. 28 . 
         FIG. 30  is an isometric view of yet another jet assembly, according to aspects of the present teachings. 
         FIG. 31  is a block diagram of a plumbing system showing how manifolds may be integrated into the system, according to aspects of the present teachings. 
         FIG. 32  is an isometric view of an air and water supply manifold, according to aspects of the present teachings. 
         FIG. 33  is a front elevational view of the manifold of  FIG. 32 . 
         FIG. 34  is a rear elevational view of the manifold of  FIG. 32 . 
         FIG. 35  is a top view of the manifold of  FIG. 32 . 
         FIG. 36  is a side elevational view of the manifold of  FIG. 32 . 
         FIG. 37  is an isometric view showing two manifolds of the type depicted in  FIGS. 32-36  attached together. 
         FIG. 38  is an isometric view of a male manifold adapter, according to aspects of the present teachings. 
         FIG. 39  is a bottom view of the male manifold adapter of  FIG. 38 . 
         FIG. 40  is a side elevational view of the male manifold adapter of  FIG. 38 . 
         FIG. 41  is an isometric view of a female manifold adapter, according to aspects of the present teachings. 
         FIG. 42  is a bottom view of the female manifold adapter of  FIG. 41 . 
         FIG. 43  is a side elevational view of the female manifold adapter of  FIG. 41 . 
         FIG. 44  is an isometric view of a manifold end cap, according to aspects of the present teachings. 
         FIG. 45  is a top view of the manifold end cap of  FIG. 44 . 
         FIG. 46  is an isometric view of an interconnected manifold assembly including two manifolds, a male manifold adapter, and a female manifold adapter, according to aspects of the present teachings. 
         FIG. 47  is an isometric view of an interconnected manifold assembly including two manifolds, a male manifold adapter, and a manifold end cap, according to aspects of the present teachings. 
         FIG. 48  is an exploded isometric view of the manifold assembly of  FIG. 46 . 
         FIG. 49  is a partially exploded isometric view of the manifold assembly of  FIG. 47 . 
         FIG. 50  is a sectional isometric view of the interconnected manifold assembly of  FIG. 46 , showing internal structure of the water conduits of the manifold assembly. 
         FIG. 51  is another sectional isometric view of the interconnected manifold assembly of  FIG. 46 , showing internal structure of the air conduits on one side of the manifold assembly. 
         FIG. 52  is a side sectional view of another embodiment of a manifold assembly including three interconnected manifold bodies and a male manifold adapter, according to aspects of the present teachings. 
         FIG. 53  is an isometric view of the manifold assembly of  FIG. 52 . 
         FIG. 54  is a block diagram illustrating how water and air flow from their respective supplies to a jet assembly, according to aspects of the present teachings. 
         FIG. 55  is an isometric view depicting a portion of an exemplary hot tub plumbing system, according to aspects of the present teachings. 
         FIG. 56  is an isometric view depicting a portion of another exemplary hot tub plumbing system, according to aspects of the present teachings. 
         FIG. 57  is an isometric view of a clamp suitable for use with dual extrusion tubing, according to aspects of the present teachings. 
         FIG. 58  is a top view of the clamp of  FIG. 57 . 
         FIG. 59  is an isometric view of a portion of an exemplary hot tub plumbing system, showing clamps of the type depicted in  FIGS. 57-58  in use. 
         FIG. 60  is a partially exploded isometric view of portions of another exemplary hot tub plumbing system, according to aspects of the present teachings. 
         FIG. 61  is a partially exploded isometric view of a magnified portion of the hot tub plumbing system of  FIG. 60 . 
         FIG. 62  is an isometric view of another clamp suitable for use with dual extrusion tubing, according to aspects of the present teachings. 
         FIG. 63  is a top view of the clamp of  FIG. 62 . 
         FIG. 64  is a sectional view of dual extrusion tubing that can be used in conjunction with presently disclosed hot tub plumbing systems, according to aspects of the present teachings. 
         FIG. 65  is a flowchart depicting steps performed in an illustrative method of installing a hot tub plumbing system, according to aspects of the present teachings. 
         FIG. 66  is a flowchart depicting steps performed in an illustrative method of coupling a jet back to a jet body, according to aspects of the present teachings. 
         FIG. 67  is a flowchart depicting steps performed in an illustrative method of attaching tubing to a jet back, according to aspects of the present teachings. 
         FIG. 68  is a flowchart depicting steps performed in an illustrative method of assembling a portion of a manifold assembly, according to aspects of the present teachings. 
         FIG. 69  is a flowchart depicting steps performed in an illustrative method of assembling another portion of a manifold assembly, according to aspects of the present teachings. 
         FIG. 70  is a flowchart depicting steps performed in an illustrative method of attaching tubing to a manifold assembly, according to aspects of the present teachings. 
         FIG. 71  is a flowchart depicting steps performed in an illustrative method of coupling air and water sources to manifold adapters, according to aspects of the present teachings. 
         FIG. 72  is an exploded side view of yet another jet assembly according to aspects of the present teachings. 
         FIG. 73  is an exploded sectional side view of the jet assembly of  FIG. 72 . 
         FIG. 74  is an isometric view of the jet assembly of  FIG. 72 . 
         FIG. 75  is an exploded side view of yet another jet assembly according to aspects of the present teachings. 
         FIG. 76  is an exploded sectional side view of the jet assembly of  FIG. 75 . 
         FIG. 77  is a sectional isometric view of yet another jet assembly according to aspects of the present teachings. 
         FIG. 78  is a sectional isometric view of yet another jet assembly according to aspects of the present teachings. 
     
    
    
     DETAILED DESCRIPTION 
     Introduction 
     As described above, hot tubs use jets to deliver a combination of water and air to various parts of a hot tub shell. In many cases, the jets may be used for massage purposes as well as circulating the water. In known approaches, the plumbing system includes two complex networks of tubing. One network delivers water from the water supply to each jet while a second network of tubing delivers air from an air supply to each jet. An example of this type of system is generally shown in  FIG. 1 . Note that  FIGS. 1 and 2  (described below) each show only a representative sample of 6 jets. A typical hot tub will contain 45 or more jets, and a larger hot tub may have 80 or more jets, potentially resulting in hundreds of separate sections of air and water tubing, each of which must be processed and installed by hand. 
     Additionally, as  FIG. 1  shows, in conventional hot tub plumbing systems, each air tube and each water tube must be coupled with an appropriate supply manifold on one end and with the back of a jet on the other. Manifolds are used to transition from a larger supply tube or pipe to the smaller tubes that attach to individual jets. These supply pipes must also be installed by hand, connecting one end to the manifold and the other to the air and/or water source. This results in many additional connections that must be installed by hand. In addition to the labor associated with such a large number of tubes and connections, there is a significant possibility that mistakes may be made during assembly. To have a functional hot tub, it is important that each tube connects to the correct locations (both the correct location on the hot tub and the correct manifold) and takes the correct path between the manifold and the jet (or between the air or water supply and the manifold). A missed or incorrect connection might result in only air or only water being delivered to a particular jet, or even two jets being connected together such that neither functions. 
     Further, in previously known plumbing systems, each connection typically requires the use of glue and/or primer, and the application of a clamp. In known methods, installing a single water tube requires cutting the tube to the correct length, sliding a clamp onto each end of the tube, applying glue to both ends of the tube and the two ports that the tube is connecting, sliding an end of the tube onto each port, and using pliers or a specialized tool to slide the clamps down over the ends of the ports. A similar process must be used for each of the air tubes, although not always requiring a clamp. Although glue is sometimes not used on the air tubes, a primer is often applied to each end of the tube, as well as to the ports to which the air tube is being coupled. 
     Hot tubs are typically assembled in a series of sequential steps. In some cases, the various steps are divided among multiple stations. For example, in one exemplary method of assembly, a worker at a first station installs the jets on the hot tub shell while a worker at a second station cuts the air and water tubes to predetermined lengths and places clamps on each end of the tubing some distance up from the ends. At the same station, a worker also couples (using glue and repositioning the clamp) one end of the water tubes to a water distribution manifold and/or couples one end of the air tubes to an air manifold. A worker at a third station installs the manifolds on the hot tub, connecting each to the appropriate supply. A worker at the third station also couples the free end of each air and water tube to the jets. 
     Coupling each tube to a jet or a manifold involves application of glue and/or primer and repositioning the clamp. Thus, glue and primer must be used at multiple stations. The workers at each station must keep track of which tube needs primer and which needs glue as well as where each tube goes. This complexity increases the likelihood of mistakes. Further, the large quantities of glue and primer used and present in the assembly area can be both a health concern and an environmental concern. 
     The present disclosure represents several improvements over the prior art: the systems and methods according to the present teachings greatly decrease the amount of labor involved in assembling a plumbing system, reduce the need for glue and primer, and decrease the likelihood of mistakes. The presently described improvements therefore represent a significant reduction in the time, labor, and cost of manufacturing a hot tub. 
     More specifically, the use of dual extrusion tubing halves the number of tubes needed to route air and water from the manifolds to the hot tub jets, as compared to the use of individual air and water tubes. Instead of using one tube to carry a stream of air to each jet and a second tube to carry a stream of water to each jet, the present disclosure teaches the use of a single length of dual extrusion tubing, having two passages, for each jet. The larger passage of the dual extrusion tubing carries a stream of water while the smaller passage, joined to the larger passage, carries a stream of air. An example of an improved system according to aspects of the present disclosure is generally shown in  FIG. 2 . 
     In addition, the present disclosure describes simplified installation of hot tub plumbing systems through the use of improved jet assemblies and manifold assemblies. For example, the present disclosure teaches simplified installation of the jets by teaching a jet assembly comprising three components. A jet insert forms the flow director and decorative portion visible from the interior of the hot tub shell. A jet body couples with the jet insert through the wall of the hot tub shell, affixing both in place. A jet back couples with the tubing and with the jet body, thereby separately delivering air and water to the jet body where the separate streams of air and water can merge before entering the hot tub body via the jet insert. 
     The present disclosure also simplifies installation by using a combined air and water manifold. In other words, instead of separate air and water manifolds, according to the present teachings a single, universal manifold can carry both air and water. The manifolds of the present disclosure are configured to have a first, larger passage for water and a second, smaller passage for air. The air passage may be joined to the outside of the water passage. In some cases, two air passages disposed on opposite sides of the water passage may be used. Parallel egress ports, one from the water passage and one from the air passage, are configured to couple with the tubing (for example, dual extrusion tubing). 
     In some cases, manifolds according to the present teachings have two sets of egress ports, each configured to couple with a dual extrusion tube. A universal manifold having two sets of egress ports allows for more flexibility in the plumbing system than known systems, for example systems which have four ports in the water manifolds and six or more in the air manifolds. According to the present teachings, because the air and water ports may be disposed together in sets (with each set including one air port and one water port), there may always be an equal number of air and water ports. 
     Moreover, a smaller number of ports on the base unit (i.e. two sets of ports on each manifold) decreases the number of unused ports in the presently disclosed systems. If there is an odd number of jets, only one set of unused ports needs to be plugged (i.e., capped). If there is an even number of jets, then manifolds can be added or removed until the number of ports exactly matches the number of jets. Note that in  FIG. 1  (the prior art), several unused air and water ports are capped while none of the ports in  FIG. 2  (an embodiment of the presently disclosed system) are unused or capped. Thus, in this manner manifolds according to aspects of the present disclosure may significantly simplify the plumbing process. 
     The systems and methods of the present teachings may also reduce the need for glue and primer, because the manifolds and the components of the jet assemblies may be configured to couple together in a water tight and air tight manner without the use of glue. For example, a ridge on the water egress and ingress ports may ensure a tight seal, while a clamp may ensure that the associated dual extrusion tubing will not slide off of the ports. A lubricant such as soapy water may be used to facilitate sliding the tubing over the ports. Such a lubricant typically does not pose the health and environmental concerns that glue and primer do. 
     The present disclosure also teaches an improved clamp having a pair of contiguous arcuate apertures which are configured to fit around the dual extrusion tubing contemplated by the present teachings. The clamp also has a releasable end portion so that the clamp can be placed over the tubing at a desired location and tightened without any need to reposition it. Two sets of complementary ratcheting teeth are engaged to secure the clamp in place. Use of this improved clamp reduces the amount that each clamp needs to be handled, further decreasing the amount of labor required. 
     The present disclosure further teaches an improved method of assembly in which many of the components may be configured to be able to be coupled together by being compressed together when aligned to overcome a resistive force. This “press-and-click” method greatly simplifies assembly, reduces the need for glue, and significantly reduces the amount of labor. The present disclosure uses “press-and-click” to refer to a connection mechanism in which two components may be fastened or engaged together by applying axial compressive forces to overcome a spring bias or other resistive force, after which the components are locked together in an air tight and/or water tight fashion. This is distinct from prior art hot tub plumbing systems in which fastening the plumbing components together typically requires gluing and press fitting individual water and air hoses to make a secure connection. 
     The plumbing system of the present disclosure may be assembled in a series of sequential steps. In some examples, the steps may be distributed between multiple stations. For example, a worker at a first station may install the jet inserts and jet bodies on the hot tub shell as well as installing any pumps and/or valves on the hot tub shell and/or hot tub frame. A worker at a second station may cut the dual extrusion tubing to predetermined lengths and attach the jet backs to the tubing using a clamp. A worker at the second station may also attach a second end of each length of dual extrusion tubing to the manifolds. In some examples, a worker at the second station may use a lubricant (e.g. soapy water) to make it easier to slide the dual extrusion tubing over the ports. 
     A worker at a third station may cut the supply pipes to the appropriate lengths and affix (using glue or primer) each end of the supply pipes to appropriate adapters. For example, a male adapter may be used to couple the supply pipe to a manifold, while a female adapter may be used to couple the supply pipe to the air and/or water sources. These adapters may be specially configured to interface with the specialized manifolds contemplated by the present teachings, as described in detail below. Since only the connection between the supply pipes and the adapters requires glue or primer, the amount of glue and primer used in the installation process is greatly decreased in comparison with current methods. Moreover, only one station (in this example, the third station) may need to use the glue and primer; this may reduce the number or workers exposed to the glue and primer, and may facilitate ventilation and other safety procedures. 
     A worker at a fourth station might install the pipes and tubing on the hot tub. This may involve using the “press-and-click” method described above to couple the supply pipes to the appropriate source, couple the other end of the supply pipes to a first manifold, couple the manifolds together, couple an end cap onto the last manifold, and couple the jet backs to the jet bodies. The use of a universal “press-and-click” method on all the components may greatly increase the efficiency of the assembly process while significantly reducing the potential for mistakes. 
     Thus, the hot tub plumbing systems of the present disclosure may result in a significant improvement over prior art, for example by decreasing the amount of labor involved during installation, decreasing the reliance on glue, and providing a simple method of simultaneously delivering separate streams of air and water with reduction in the likelihood of mistakes during assembly. 
     Various aspects and examples of a hot tub plumbing system configured to simultaneously deliver both air and water to each jet and having components configured to be assembled in a universal “press-and-click” method, as well as related methods, are described below and illustrated in the associated drawings. Unless otherwise specified, a hot tub plumbing system and/or its various components may, but are not required to, contain at least one of the structures, components, functionalities, and/or variations described, illustrated, and/or incorporated herein. Furthermore, unless specifically excluded, the process steps, structures, components, functionalities, and/or variations described, illustrated, and/or incorporated herein in connection with the present teachings may be included in other similar devices and methods, including being interchangeable between disclosed embodiments. The following description of various examples is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. Additionally, the advantages provided by the examples and embodiments described below are illustrative in nature and not all examples and embodiments provide the same advantages or the same degree of advantages. 
     Definitions 
     The following definitions apply herein, unless otherwise indicated. 
     “Substantially” means to be more-or-less conforming to the particular dimension, range, shape, concept, or other aspect modified by the term, such that a feature or component need not conform exactly. For example, a “substantially cylindrical” object means that the object resembles a cylinder, but may have one or more deviations from a true cylinder. Similarly, “substantially parallel” structures are structures that are generally parallel, but that could have slight deviations from parallel, for instance due to manufacturing tolerances or slight assembly misalignments. 
     “Comprising,” “including,” and “having” (and conjugations thereof) are used interchangeably to mean including but not necessarily limited to, and are open-ended terms not intended to exclude additional, unrecited elements or method steps. 
     Terms such as “first”, “second”, and “third” are used to distinguish or identify various members of a group, or the like, and are not intended to show serial or numerical limitation. 
     “Coupled” means connected, either permanently or releasably, whether directly or indirectly through intervening components. 
     “Hot tub” and “hot tub plumbing system” are used throughout this disclosure to mean any equipment that uses jets to provide mixed streams of air and water. This includes not only conventional spas, but also swim spas, therapy pools and the like. 
     “In fluid communication” is used to describe parts which are coupled (whether directly or indirectly through intervening components) in such a way that a fluid, liquid, gas, and/or any other suitable substance capable of flowing, running, and/or moving in a fluid manner can move freely between the parts. Parts may be in direct fluid communication, wherein the substance can move directly from one part to the other and/or vice versa. Parts also may be in indirect fluid communication, wherein the substance can move from one part to an intermediate part or parts and from the intermediate parts or parts to the second part and/or vice versa. 
     Terms such as “upstream” and “downstream” are used to indicate a relative position and/or orientation with respect to the principal or expected direction of flow of fluid, liquid, gas, and/or other suitable substance. For example, an “upstream end” of an object is the end of the object that a moving fluid encounters first when the fluid is flowing in an expected direction, whereas a “downstream end” of the object is the end of the object that a moving fluid encounters last when the fluid is flowing in an expected direction. 
     Overview 
     In general, a hot tub plumbing system according to the present teachings may include jet inserts, jet bodies, and jet backs (which collectively may be referred to as a “jet assembly”), manifolds, manifold adapters, and manifold end caps (which collectively may be referred to as a “manifold assembly”), clamps, and/or dual extrusion tubing that carries both air and water. These components may be used together in an integrated plumbing system that provides numerous advantages over more conventional hot tub plumbing systems. 
       FIG. 3  is an illustrative block diagram of an exemplary hot tub, generally indicated at  100 , having an improved plumbing system. Hot tub  100  includes a hot tub frame  102  which contains and supports a hot tub shell  104  and the plumbing system which provides air and water to hot tub shell  104 . Hot tub shell  104  may also be referred to as a hot tub body or a hot tub body portion. The plumbing system of hot tub  100  includes a water supply  106  which connects with a valve  108 . Valve  108  is connected to an adapter  110  via a pipe  112 . Water supply  106 , valve  108 , and pipe  112  may include any suitable structures configured to provide water to adapter  110 . 
     In some examples, pipe  112  may be a 2-inch pipe configured to carry water from valve  108  to adapter  110 . In some examples, water supply  106  may include a water pump, a heating system, and/or a filtering system. In some examples, water supply  106  may receive water from a drain or water output structure of hot tub shell  104  such that hot tub  100  recycles water, for example, by passing it through a heating and/or filtering system. In some examples, valve  108  may be directly coupled to water supply  106 . In some examples, valve  108  may be coupled indirectly to water supply  106  via a length of pipe and/or an adapter. 
     Hot tub  100  also includes an air supply  114  and air tubing  116  which connects air supply  114  to adapter  110 . Air supply  114  and air tubing  116  may include any suitable structures configured to provide air to adapter  110 . In some examples, hot tub  100  may use environmental air and air supply  114  may include a vent to the exterior of hot tub  100 , such that air for the air supply is drawn in through the vent by negative pressure. In some examples, air supply  114  may include a vent configured to have a variable opening, the size of which may be adjusted by a user to control the ratio of air and water delivered by the jets of the hot tub. 
     Adapter  110  couples with a first of one or more manifolds  118 . Each of the one or more manifolds  118  connects with a length of tubing  120  which in turn connects with a jet back  122 . Each jet back  122  couples to a jet body  124 , and each jet body  124  couples to hot tub shell  104  and a jet insert  126 . Additionally, or alternatively, the jet insert may be referred to as a jet face. In some examples, jet body  124  may couple to hot tub shell  104  and jet insert  126  may couple to a portion of jet body  124  that is disposed inside hot tub shell  104 . In some examples, jet insert  126  may couple to hot tub shell  104  and jet body  124  may couple to a portion of jet insert  126  that is disposed outside hot tub shell  104 . In some examples, jet body  124  and jet insert  126  couple together to form a unit, or are integrally formed as a single component, which couples to hot tub shell  104 . In some examples, tubing  120  may be dual extrusion tubing which has two separate passages, for air and water respectively. In some examples, tubing  120  may include separate lengths of tubing for air and water. 
     Adapter  110  separately provides air and water to the first of one or more manifolds  118 . Each of the one or more manifolds  118  simultaneously may pass a first portion of the air and water as separate streams to another downstream component while allowing a second portion of the air and water to pass as separate streams to tubing  120  and thence to a jet back  122 . Additionally, or alternatively, the separate air and water streams may be referred to as separate air and water supply streams. In some examples, coupling manifold  118  to tubing  120  may include using a clamp. 
     In some examples, manifold  118  passes the first portion of the air and water to another manifold. In some examples, manifold  118  passes the first portion of air and water to an adapter  128 . Adapter  128  may couple to another length of pipe (similar to pipe  112 ), another adapter  110 , and/or another manifold  118 . Adapter  128  may couple to a length of pipe in cases where multiple clusters of manifolds  118  are needed, in which case the same water and air supplies may provide water and air to all of the different sets of manifolds. In some examples, it may be advantageous to have a plurality of clusters of manifolds spaced out at different portions of hot tub  100  to better reach each jet with the least amount of tubing. Any suitable number of manifolds grouped in any suitable number and/or size of clusters may be used. 
     An end cap  130  may be coupled with at least one of the one or more manifolds  118 . In some examples, end cap  130  may be coupled with a last manifold  118  to end the flow of air and water and to ensure the plumbing system is sealed. In some examples, only one cluster of manifolds may be used and the last manifold may be coupled with end cap  130 . In some examples, hot tub  100  may include several groups and/or clusters of manifolds and the manifold at the end of the last cluster may be coupled with end cap  130 . In some cases, a separate end cap may not be required. For example, one of manifolds  118  or adapters  128  may be formed with integral caps or seals. 
     Each section of tubing  120  may provide separate streams of air and water to a jet back  122 . In some examples, coupling tubing  120  to jet back  122  may include using a clamp. Jet back  122  provides separate streams of air and water to jet body  124 . In some examples, jet body  124  may be configured to merge the streams of air and water before delivering the air and water mixture to hot tub shell  104  via jet insert  126 . In some examples, jet body  124  may include a nozzle formed as an integral part of jet body  124 . In some examples, a separate nozzle may be press-fit into jet body  124 . In some examples, jet insert  126  may include a flow director. In some examples, jet insert  126  may be visible to a user inside hot tub shell  104  and may include decorative portions. 
     In some examples, some of the components of hot tub  100  may be configured to be able to be coupled together when aligned by being compressed together to overcome a resistive force. As described above, the present disclosure uses “press-and-click” to refer to a connection mechanism in which two components may be fastened or engaged together by applying axial compressive forces to overcome a spring bias or other resistive force, after which the components are locked together in some fashion. This is distinct from prior art hot tub plumbing systems in which fastening the plumbing components together typically requires gluing and press fitting to make a secure connection. In some examples, a “press-and-click” assembly method may be facilitated by features of the components such as spring-biased clips, retaining features, and O-rings. 
     In some examples, two components locked together by a “press-and-click” method may be able to be unlocked and/or uncoupled. In other words, a “press-and-click” method may include releasably coupling two components. Releasably coupling components together may be advantageous as it may, for example, allow a worker to uncouple components that were coupled together by mistake, or for the purpose of replacing damaged or defective components. 
     In some examples, adapter  110  may be configured to couple to manifold  118  by the glueless “press-and-click” method. In some examples, each of one or more manifolds  118  may be configured to couple to other manifolds  118  and/or adapters  110  and  128  by the glueless “press-and-click” method. In some examples, end cap  130  may be configured to couple to manifolds  118  by the glueless “press-and-click” method. In some examples, adapter  110 , each of one or more manifolds  118 , adapter  128 , and/or end cap  130  may be configured to be coupled together interchangeably such that any number of components may be used in any suitable order. 
     In some examples, jet back  122  and jet body  124  may be configured to be coupled together by the glueless “press-and-click” method. In some examples, jet body  124  and jet insert  126  may be configured to be coupled together by the glueless “press-and-click” method. In some examples, jet body  124  and jet insert  126  may be configured to be releasably coupled together without the use of glue and/or by, for example, aligning the components and rotating one with respect to the other. For example, rotating the jet body with respect to the jet insert may engage hooks within each of the components. 
     Examples, Components, and Alternatives 
     The following sections describe selected aspects of exemplary hot tub plumbing systems as well as related systems and/or methods. The examples in these sections are intended for illustration and should not be interpreted as limiting the entire scope of the present disclosure. Each section may include one or more distinct embodiments or examples, and/or contextual or related information, function, and/or structure. 
     A. Illustrative Jet Assembly 
     As shown in  FIGS. 4-30 , this section describes a jet assembly  200  according to aspects of the present teachings. Additionally, or alternatively, a jet assembly may be referred to as a jet. Jet assembly  200  includes a jet back  202 , a jet body  204 , and a jet insert  206 , which are respectively examples of jet back  122 , jet body  124 , and jet insert  126  described above more generally. Additionally or alternatively, the jet insert may be referred to as a jet face. In some embodiments, jet assembly  200  may further include a nozzle  208 . 
     Overview 
       FIG. 4  is a block diagram of an illustrative jet assembly, generally indicated at  200 , having a jet back  202 , a jet body  204 , and a jet insert  206 . Jet assembly  200  may include any suitable structures configured to couple tubing  120  with hot tub shell  104  such that tubing  120  is in fluid communication with the interior of hot tub shell  104 . For example, jet assembly  200  may include a jet back which couples to tubing  120  and to a jet body; the jet body may couple to hot tub shell  104  and/or a jet insert. In some examples, jet assembly  200  may merge separate streams of air and water before passing the air and water mixture to hot tub shell  104 . Tubing  120  and hot tub shell  104  are also schematically depicted in  FIG. 4 . Nozzle  208  is depicted in dashed lines to indicate that it may be included in some, but not all, embodiments. 
     Jet back  202  may include any suitable structure configured to couple with tubing  120 , receive streams of air and water from tubing  120 , releasably couple with jet body  204 , and pass the streams of air and water to jet body  204 . For example, jet back  202  may include a water ingress port and an air ingress port which together form a set of ingress ports. In some examples, jet back  202  may further include a central portion configured to couple to and form a water tight seal with jet body  204 . In some examples, the set of ingress ports may be configured to couple with dual extrusion tubing. In some examples, the set of ingress ports of jet back  202  may be configured to couple with separate lengths of tubing for air and for water. In some examples, coupling jet back  202  with tubing  120  may include the use of one or more clamps. 
     Jet body  204  may include any suitable structure configured to couple with jet back  202 , to couple with jet insert  206  and/or hot tub shell  104 , and to pass the air and water (either mixed or as separate streams) to hot tub shell  104 . Jet body  204  may be further configured to form a water tight seal with jet back  202 . In some examples, forming a water tight seal with jet back  202  may include the use of one or more O-rings. In some examples, jet body  204  may be further configured to merge the separate streams of air and water. In some examples, jet bodies  204  having different dimensions may be used to couple with jet inserts  206  having various sizes and/or styles. 
     Jet insert  206  may include any suitable structure configured to couple with jet body  204  and/or hot tub shell  104 , and to pass the mix of air and water to the interior of hot tub shell  104 . In some examples, some or all of jet insert  206  may be visible from the interior of hot tub shell  104  and/or jet insert  206  may further include decorative portions or features. In some examples, jet insert  206  may include a flow director which may be configured to increase the speed of and/or change the direction of the air and water mixture. 
     Any suitable method of coupling jet body  204  and jet insert  206  together and affixing the combination to hot tub shell  104  may be used. In some examples, jet body  204  attaches to hot tub shell  104  and jet insert  206  couples to a portion of jet body  204  which is disposed within hot tub shell  104  (this example is schematically depicted by solid lines in  FIG. 4 ). In some examples, jet insert  206  attaches to hot tub shell  104  and jet body  204  couples to a portion of jet insert  206  which is disposed outside hot tub shell  104  (this example is schematically depicted by dashed line  210  in  FIG. 4 ). In some examples, both jet body  204  and jet insert  206  may be attached to hot tub shell  104  as well as coupled together. 
     In some examples, jet assembly  200  may further include nozzle  208 . Nozzle  208  may include any suitable structure for increasing the speed of the water, controlling the direction of the water, and/or merging the streams of air and water. In some examples, nozzle  208  may include a separate piece which is press-fit into jet body  204 . In some examples, nozzle  208  may include a structure formed as an integral part of jet back  202  and/or jet body  204 . In some examples, nozzle  208  may be omitted. 
     In some examples, some of the components of jet assembly  200  may be configured to be able to be coupled together when aligned by being compressed together to overcome a resistive force. As described above, the present disclosure uses “press-and-click” to refer to a connection mechanism in which two components may be fastened or engaged together by applying axial compressive forces to overcome a spring bias or other resistive force, after which the components are locked together in some fashion. 
     More specifically, in some examples, jet back  202  and jet body  204  may be configured to be coupled together by a glueless “press-and-click” method. In some examples, attachment structures such as spring biased clips and retaining features may be used to facilitate a “press-and-click” method of assembly. Additionally, or alternatively, features such as O-rings may be used to ensure a water tight seal between components. 
     Similarly, in some examples, jet body  204  and jet insert  206  may be configured to be coupled together by the glueless “press-and-click” method. In some examples, jet body  204  and jet insert  206  may be configured to be coupled together without the use of glue and/or by a mechanism other than a “press-and-click” method. For example, jet body  204  and jet insert  206  may be configured to be coupled together by a method which includes aligning the components and rotating one with respect to the other. In some examples, rotating jet body  204  with respect to jet insert  206  may engage attachment structures such as hooks within each of the components. 
     This section includes a description of various possible embodiments of jet assembly  200 , according to aspects of the present teachings. A person of ordinary skill in the art will recognize that other embodiments or variations are possible within the scope of the present teachings. 
     First Straight Back Embodiment 
       FIGS. 5 through 19  depict a first embodiment  300  of general jet assembly  200 , which includes a straight back jet back. In the present teachings, a jet assembly may sometimes be referred to simply as a “jet.” The first embodiment of jet assembly  200  is generally indicated at  300  and includes a jet back  302 , a jet body  304 , and a nozzle  308 . Jet assembly  300  also may include a jet insert, or jet face (not shown). Additionally, or alternatively, jet back  302  may be referred to as a straight back jet back or a straight jet back. Jet back  302  is an example of jet back  202  described above, jet body  304  is an example of jet body  204  described above, a compatible jet insert would be an example of jet insert  206  described above, and nozzle  308  is an example of nozzle  208  described above. 
       FIGS. 5-19  show various views of straight back jet  300  and components thereof.  FIG. 5  shows an exploded sectional view of jet  300 .  FIG. 5  depicts illustrative embodiments of jet back  302 , jet body  304 , and nozzle  308 .  FIG. 6  is a partially assembled isometric view of straight jet assembly  300  in which nozzle  308  is press fit into jet body  304 .  FIG. 7  depicts a fully assembled isometric view of straight jet  300 .  FIG. 8  is a sectional view of a fully assembled straight back jet assembly  300  and depicts how the components of straight jet assembly  300  fit together.  FIG. 9  depicts an isometric view of jet back  302 .  FIG. 10  is a side isometric view of nozzle  308 , and  FIG. 11  is a rear isometric view of nozzle  308 .  FIG. 12  depicts nozzle  308  press fit into jet body  304  and the O-rings installed on jet body  304 .  FIG. 13  is a front isometric view of jet body  304 . As discussed below,  FIGS. 14-19  depict various views of alternate embodiments of jet body  304 . Note that  FIGS. 5-19  do not show a jet insert. However, as discussed in greater detail below, jet body  304  is configured to couple with one or more jet inserts (e.g., see jet insert  506  in  FIG. 22 ). 
     As seen in  FIG. 5 , straight back jet assembly  300  includes jet back  302 , nozzle  308 , jet body  304 , and may include a jet insert (not shown). Jet back  302  includes two parallel ingress ports: a water ingress port  310  and an air ingress port  312 . Water ingress port  310  is larger than air ingress port  312  and is substantially centered on a longitudinal axis  314  of the jet back. Additionally, or alternatively, the water ingress port may be referred to as a water barb. Water ingress port  310  includes a lip or ridge  316  as can best be seen in  FIGS. 6 and 7 . Lip  316  may include any suitable structure configured to ensure a water tight seal between water ingress port  310  and a length of tubing (such as tubing  120 ). For example, lip  316  may include a sloped ridge as can best be seen in  FIGS. 6 and 7 . Air ingress port  312  is parallel to water ingress port  310  and is offset from the center of jet back  302 . Additionally, or alternatively, the air ingress port may be referred to as an air barb. In some examples, air ingress port  312  may include a lip or other feature to ensure a seal. In some examples, an external portion of air ingress port  312  may be smooth, as can best be seen in  FIGS. 6 and 7 . 
     In the embodiment shown in  FIGS. 5-9 , jet back  302  is configured to couple with dual extrusion tubing having two parallel passages joined at a periphery (examples of dual extrusion tubing are discussed in more detail below). In some examples, jet back  302  may be configured to couple with any other suitable kind of tubing. For example, jet back  302  may be configured to couple with two separate lengths of tubing, one which carries air and one which carries water. In some examples, configuring jet back  302  to couple with different kinds of tubing may include changing the spacing between the air and water ingress ports and/or the dimensions for the air and water ingress ports. 
     Jet back  302  further includes a central portion  318  configured to create a water tight seal with jet body  304 . Central portion  318  is in direct fluid communication with water ingress port  310  and air ingress port  312  and may include any suitable shape depending on the application and on the characteristics of the jet body. For example, central portion  318  may be substantially cylindrical as can best be seen in  FIGS. 6, 7, and 9 . In some examples, central portion  318  may be substantially rectangular or substantially triangular. 
     Jet body  304  includes an upstream portion  320  and a downstream portion  322 . Upstream portion  320  may include any suitable structure configured to be at least partially disposed within central portion  318  of the jet back. For example, as can be best seen in  FIGS. 6, 7, and 12 , upstream portion  320  may be substantially cylindrical. In some examples, downstream portion  322  may have substantially the same cross-section as upstream portion  320 . For example, downstream portion  322  may be substantially cylindrical as in  FIGS. 6, 7, and 12 . Downstream portion  322  may further include any suitable structure configured to engage with hot tub shell  104  and/or a jet insert  206 . For example, downstream portion  322  may include a flange  324 . Downstream portion  322  will be discussed in further detail below. 
     Jet back  302  includes an attachment mechanism extending from a first end  326  of central portion  318  and configured to attach the jet back to jet body  304  in a secure manner. The attachment mechanism may include any suitable structure depending on the characteristics of the jet body and the jet back. For example, a plurality of spring biased clips  328  may be configured to couple with a retaining feature, such as a groove  330 , on jet body  304 . In some examples, groove  330  may be formed as part of upstream portion  320  and/or may be disposed between upstream portion  320  and downstream portion  322 . In the embodiment shown in  FIGS. 5-9 , jet back  302  includes four spring biased clips  328  (see, for example,  FIG. 6 ). Spring biased clips  328  may include a resiliently flexible support  332  and a sloped lip  334  which is configured to engage with groove  330 . Groove  330  may include any suitable structure and jet back  302  may include any suitable number and/or shape of spring biased clips  328  or other similar structures configured to couple with groove  330  in a complementary manner. 
     In some examples, the attachment mechanism may be configured to couple jet back  302  to jet body  304  while allowing jet back  302  to rotate relative to jet body  304 . In other words, in some examples, jet back  302  may able to rotate about longitudinal axis  314  when coupled to jet body  304  while maintaining a water-tight and air-tight seal; this may allow a worker to prevent adjacent jet assemblies from interfering with each other, by rotating them as needed. 
     In addition to groove  330 , jet body  304  includes recesses  336  configured to contain one or more O-rings  338 . Recesses  336  may include any suitable structure for retaining O-rings  338  depending on the characteristics of the jet back, the jet body, and the O-rings. For example, recesses  336  may include narrow channels disposed on upstream portion  320 , such as those shown, for example, in  FIG. 13 . In some examples, recesses  336  may be configured such that the outside edge of the O-ring is flush with or extends slightly beyond the surface of the upstream portion of the jet body as shown in  FIGS. 5, 6, 8 and 12 . Allowing the O-ring to extend slightly beyond the surface of the jet body may ensure a water tight seal by compressing the O-ring slightly between an inner surface of the central portion of the jet back and the bottom and sides of recesses  336 . In some examples, jet body  304  includes two recesses  336  to accommodate two O-rings  338  as in  FIGS. 5-8 and 12 . In some examples, jet body  304  may include some other suitable number of O-rings disposed in a similar number of recesses. 
     As can be seen in  FIG. 9 , jet back  302  also includes a spacing mechanism configured to ensure sufficient space between a proximate end  340  of upstream portion  320  of jet body  304  and an inner wall  342  of jet back  302 . The spacing mechanism may include any suitable structure depending on the characteristics of the jet body and the jet back. For example, a plurality of spacers  344  may be disposed on inner wall  342  and configured to prevent proximate end  340  of the jet body from becoming flush with inner wall  342 . In some examples, spacers  344  may be rectangular blocks formed as an integral part of jet back  302 . In the example shown in  FIG. 5 , jet back  302  includes four spacers  344 . In some examples, jet back  302  may include any other suitable number of spacers  344 , or a continuous spacer. 
     In the embodiment shown in  FIGS. 5-12 , nozzle  308  is formed as a separate piece from the jet back and the jet body and is configured to be press fit into the jet body. In this embodiment, nozzle  308  includes a main body  346  and a conical portion  348 . Main body  346  may include any suitable structure depending on the characteristics of the jet body. For example, main body  346  may include a hollow, substantially cylindrical tube as best seen in  FIGS. 10-11 . Conical portion  348  may include any suitable structure depending on the application and the characteristics of the jet body and the jet back. 
     For example, conical portion  348  may taper from a larger, round first aperture  350  to a smaller, round second aperture  352  as seen in  FIG. 11 . In some examples, conical portion  348  may include a constant-diameter, annular flange  354  attached to first aperture  350 . Nozzle  308  further includes support structures  356 . Support structures  356  may include any suitable structure configured to connect conical portion  348  with main body  346 , depending on the application and the characteristics of the main body and the conical portion of the nozzle. For example, support structures  356  may include a plurality of substantially rectangular support struts as can be seen in  FIGS. 10-11 . In some examples, nozzle  308  may include four support structures  356 . 
     In this embodiment, nozzle  308  is configured to be press-fit into jet body  304 . As shown in  FIGS. 6 and 12 , main body  346  is configured to fit at least partially within a main cavity  358  of jet body  304 . For example, an outer diameter of main body  346  may be very close to the inner diameter of main cavity  358  to ensure a secure fit. In some examples, main body  346  may have a slight taper to create a wedge fit between nozzle  308  and main cavity  358 . Main cavity  358  may be primarily disposed within upstream portion  320 . As seen in  FIG. 8 , conical portion  348  is configured to fit within a recessed portion  360  of inner wall  342  when jet back  302  is coupled with jet body  304 . Support structures  356  may be further configured to leave gaps  362  between the conical portion  348 , main body  346 , and support structures  356 . When jet back  302  is coupled to jet body  304 , water from water ingress port  310  may be passed through first aperture  350  and second aperture  352  while air from air ingress port  312  may be passed into an air chamber  364  and through gaps  362 . The air and water may mix in main cavity  358  of the jet body and/or within the main body  346  of the nozzle before passing through a main aperture  366  of the jet body. 
       FIGS. 12 and 13  show isometric views of the jet body  304  of the current embodiment. Main aperture  366  connects main cavity  358  with a receiving chamber  368 . Receiving chamber  368  is primarily disposed within downstream portion  322  and may include any suitable structure for receiving at least a portion of a jet insert. For example, receiving chamber  368  may include a substantially cylindrical cavity as shown in  FIGS. 12 and 13 . In some examples, receiving chamber  368  may include a rectangular and/or triangular cavity. 
     A plurality of hooks  370  are disposed inside of receiving chamber  368 . Hooks  370  may include any suitable structure for engaging a jet insert. In the embodiment shown in  FIG. 13 , hooks  370  include an approximately U-shaped structure wherein one side is shorter than the other. In some examples, hooks  370  may include an approximately L-shaped structure. A jet insert having similarly shaped teeth may be inserted into the receiving cavity such that the hooks and teeth are offset and rotated until the hooks and teeth engage. Jet body  304  may include any suitable number of hooks  370 . For example, the embodiment shown in  FIG. 13  includes two hooks  370 . In some examples, receiving chamber  368  may include other suitable structures for coupling to and suitably positioning a jet insert with respect to jet body  304 . 
     A jet insert may include any suitable structure configured to pass a mixture of air and water to the interior of hot tub body  104 . In some examples, some or all of the jet insert may be visible from the interior of hot tub body  104  and/or the jet insert may include decorative portions. In some examples, the jet insert may include any suitable structures configured to manipulate the speed, direction, and/or other properties of the stream of air and water. For example, the jet insert may include a flow director and/or a rotating nozzle. 
     Jet assembly  300  may include, or be compatible with, multiple versions of a jet insert. For example, a plurality of different jet inserts may be configured to couple with jet body  304 . In other words, the same style of jet body may be installed in multiple places on a hot tub  100  and different styles of jet insert may be coupled to each jet body depending on the location within the hot tub and desired application. Different jet inserts may be chosen, for example, to provide different flow characteristics and/or for decorative reasons. 
     Additionally, or alternatively, jet assembly  300  may include, or be compatible with, multiple versions of jet body  304 . For example, a plurality of different sizes and/or styles of jet body  304  may be configured to couple with a single style of jet back  302 . Each version of jet body  304  may be configured to couple with one or more versions of the jet insert. In other words, a variety of styles of jet body may be installed in multiple places on a hot tub  100  and different styles of jet insert may be coupled to each jet body depending on the location within the hot tub and the features of the jet body. Different jet bodies may be used, for example, to provide different flow characteristics or to couple with different styles of jet inserts. 
     As discussed above,  FIGS. 12-13  depict a first style of jet body  304 .  FIGS. 14-19  depict three other styles of jet body  304  indicated at  304   a ,  304   b , and  304   c  respectively. With the exception of the diameter of downstream portion  322  and certain features of receiving chamber  368 , jet bodies  304   a ,  304   b , and  304   c  are substantially similar to jet body  304 . Accordingly, similar features will be denoted with similar reference numbers and will not be discussed here. Features of receiving chamber  368 , such as hooks  370 , may differ between jet bodies  304 ,  304   a ,  304   b , and  304   c  to best couple and position a suitable version of the jet insert within each jet body. Jet body  304  and the jet insert may include any suitable structures configured to couple the jet body and jet insert together. For example, jet body  304  and the jet insert may be coupled together using hooks, clips, threaded engagement, and/or any other suitable method. While jet bodies  304 ,  304   a ,  304   b  and  304   b  are described below as have particular dimensions, according to the present teachings, a jet body may have any suitable dimensions for a particular application 
     In the embodiment depicted in  FIGS. 12-13 , downstream portion  322  of jet body  304  has a maximum diameter of approximately 1.9 inches. Jet body  304  includes additional protrusions  374  disposed on an inner wall  372  of receiving chamber  368 . As shown in  FIG. 13 , jet body  304  includes two substantially rectangular protrusions  374 . Protrusions  374  may be used as a spacing mechanism to ensure sufficient space between a proximate end of a jet insert and inner wall  372  of receiving chamber  368 . Additionally, flange  324  on downstream portion  322  includes a channel  376 . 
     Jet body  304   a  is shown in  FIGS. 14-15  and includes a downstream portion  322  having a maximum diameter of approximately 2.7 inches. Jet body  304   a  includes two hooks  370 . Jet body  304   a  further includes an annular flange  378  disposed adjacent main aperture  366  and two slots  380  disposed on flange  324 . Annular flange  378  and slots  380  may be configured to facilitate coupling with and positioning a jet insert in conjunction with hooks  370 . 
       FIGS. 16 and 17  show jet body  304   b . Jet body  304   b  includes a downstream portion  322  having a maximum diameter of approximately 3.2 inches. Jet body  304   b  includes four hooks  370  and a flange  324 . Flange  324  includes a channel  376  and four slots  380  disposed within channel  376 . 
       FIGS. 18 and 19  show jet body  304   c . Jet body  304   c  includes a downstream portion  322  having a maximum diameter of approximately 4.5 inches. Jet body  304   c  includes a flange  324  and four spring biased clips  382  configured to engage with a suitable style of jet insert. 
     Each of jet body  304 , jet body  304   a , jet body  304   b , and jet body  304   c  may be used and installed in hot tub shell  104  in substantially the same way or similar ways. Further, each style of jet body may couple with nozzle  308  and jet back  302  in a substantially similar way. 
     During installation, jet assembly  300  may be assembled in multiple steps and/or at multiple stations. A first assembly step may include press fitting nozzle  308  into main cavity  358  of jet body  304  (see  FIG. 12 ) and coupling the air and water ingress ports of jet back  302  with tubing  120 , which may be dual extrusion tubing. In some examples, press-fitting nozzle  308  into main cavity  358  may include using a lubricant (for example, soapy water). In some examples, press-fitting nozzle  308  into main cavity  358  may include the application of an adhesive and/or primer. 
     Coupling the air and water ingress ports of jet back  302  with tubing  120  may include any suitable process and/or structure. For example, tubing  120  may be slid over the ends of the air and water ingress ports of jet back  302  and a clamp (described in more detail below) may be used to prevent the tubing from sliding off. In some examples, a lubricant (e.g., soapy water) may be used to facilitate sliding the tubing over the ingress ports. In some examples, tubing  120  may include dual extrusion tubing. In some examples, tubing  120  may include separate air and water tubes which may be installed one at a time on the air and water ingress ports respectively. 
     Another step in assembling jet assembly  300  may include installing jet body  304  and a jet insert in hot tub shell  104 . For example, jet body  304  (with nozzle  308 ) may be inserted into a hole formed in the shell of hot tub shell  104 . Jet body  304  may be inserted from the interior of hot tub shell  104  and may be secured to hot tub shell  104  by any suitable mechanism configured to be water tight and secure. For example, jet body  304  may attach to hot tub shell  104  via threaded engagement, glue, press-fitting, and/or any other suitable attachment mechanism. In some examples, attaching jet body  304  to hot tub shell  104  may include threading the jet body into the hot tub shell and/or the use of a compressive gasket. 
     A jet insert may be coupled to jet body  304  from the interior of hot tub shell  104  after jet body  304  has been installed in hot tub shell  104 . As discussed above, jet body  304  is configured to securely couple with and position a jet insert. In some examples, jet body  304  and/or the jet insert may be installed from the exterior of hot tub shell  104 . In some examples, jet body  304  and the jet insert may couple together through a hole in the hot tub shell, thereby attaching both parts to the hot tub shell. In some cases, coupling the jet body and the jet insert together may partially or entirely fix the jet assembly in place relative to the hot tub shell. 
     The installation of jet assembly  300  further includes coupling jet back  302  (which is attached to tubing  120 ) to jet body  304  (which includes nozzle  308  and is attached to hot tub shell  104  and a jet insert). Jet back  302  may be coupled with jet body  304  by a “press-and-click” method (described above). For example, jet back  302  and jet body  304  may be aligned and then compressed together to overcome the resistive force of spring biased clips  328 . In the embodiment shown in  FIGS. 5-19 , spring biased clips  328  are configured to flex outward, away from a default position (e.g., away from longitudinal axis  314 ), when sloped lip  334  slides over proximate end  340  of jet body  304  and along an external portion of upstream portion  320 . Spring biased clips  328  are further configured to snap back into the default position (e.g., back towards longitudinal axis  314 ) when sloped lip  334  encounters groove  330  of jet body  304 . Sloped lip  334  engages with groove  330  and prevents spring biased clips  328 , and thus jet back  302 , from sliding towards proximate end  340  and off of jet body  304 . Thus, jet back  302  and jet body  304  are coupled together. 
     In some examples, jet back  302  and jet body  304  may be configured to be able to be unlocked and/or uncoupled. Uncoupling jet back  302  from jet body  304  may be accomplished by moving spring biased clips  328  away from jet body  304  (e.g., away from longitudinal axis  314 ) and sliding the jet back off of the jet body. In some examples, a worker may accomplish this using a finger to move the spring biased clips and/or using a tool. Releasably coupling the jet back and the jet body together may be advantageous as it may, among other advantages, allow a worker to uncouple a jet back that was coupled to the wrong jet body by mistake. 
     Each of the components of jet assembly  300  (e.g., jet back  302 , jet body  304 , a jet insert, and nozzle  308 ) may be constructed out of any suitable material. For example, the components of jet assembly  300  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). The components of jet assembly  300  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     Second Straight Back Embodiment 
       FIGS. 20-21  depict a second embodiment  400  of a general jet assembly  200 , which also includes a straight back jet back. The second embodiment of jet assembly  200  is generally indicated at  400  and includes a jet back  402 , a jet body  404 , and also may include a jet insert (or jet face). A nozzle  408  includes a structure formed as an integral part of jet back  402 . Additionally, or alternatively, jet back  402  may be referred to as a straight back jet back or a straight jet back. Jet back  402  is an example of jet back  202  described above, jet body  404  is an example of jet body  204  described above, and a suitable jet insert would be an example of jet insert  206  described above. Many of the features of second embodiment  400  of jet assembly  200  are the same as in first embodiment  300 . Accordingly, similar components may be labeled with similar reference numbers and only an abbreviated discussion of such features will be provided here. The differences between the embodiments are described in detail below. 
       FIGS. 20-21  show various views of straight back jet  400  and components thereof.  FIG. 20  depicts a partially exploded view of straight back jet assembly  400 .  FIG. 21  is a front view of jet back  402  of straight back jet assembly  400 . Note that  FIGS. 20-21  do not show a jet insert. However, as discussed, jet body  404  is configured to couple with a suitable jet insert, and various styles of jet insert may be compatible with jet body  404  and configured to provide desired ornamental and functional features. 
     As seen in  FIG. 20 , straight back jet assembly  400  includes jet back  402 , nozzle  408 , jet body  404 , and a jet insert (not shown). As with jet  300 , jet back  402  includes two parallel ingress ports: a water ingress port  410  and an air ingress port  412 . Water ingress port  410  is substantially centered on a longitudinal axis  414  of the jet back and includes a lip or ridge  416  as can best be seen in  FIG. 20 . Air ingress port  412  is parallel to water ingress port  410  and is offset from the center of jet back  402 . 
     In the embodiment shown in  FIGS. 20-21 , jet back  402 —similar to jet back  302 —is configured to couple with dual extrusion tubing having two parallel passages joined at a periphery (examples of dual extrusion tubing are discussed in more detail below). In some examples, jet back  402  may be configured to couple with any other suitable kind of tubing. Similar to jet back  302 , jet back  402  further includes a central portion  418  configured to create a water tight seal with jet body  404 . Central portion  418  is in direct fluid communication with water ingress port  410  and air ingress port  412  and may include any suitable shape depending on the application and on the characteristics of the jet body. In this embodiment, central portion  418  is substantially cylindrical as can best be seen in  FIGS. 20 and 21 . 
     As in the previous embodiment, jet body  404  includes an upstream portion  420  and a downstream portion  422  wherein the upstream portion is configured to be at least partially disposed within central portion  418  of jet back  402 . Jet back  402  includes an attachment mechanism extending from a first end  426  of central portion  418  and configured to couple the jet back to jet body  404  in a secure manner. The attachment mechanism, like the attachment mechanism for jet  300 , includes a plurality of spring biased clips  428  which are configured to couple with a retaining feature, such as a groove  430 , on jet body  404 . In the embodiment shown in  FIGS. 20-21 , jet back  402  includes four spring biased clips  428  (as best seen in  FIG. 21 ). In some examples, spring biased clips  428  may include a resiliently flexible support  432  and a sloped lip  434  which is configured to engage with groove  430 . 
     In some examples, the attachment mechanism may be configured to couple jet back  402  to jet body  404  while allowing jet back  402  to rotate relative to jet body  404 . In other words, in some examples, jet back  402  may able to rotate about longitudinal axis  414  when coupled to jet body  404  while maintaining a water- and air-tight seal; this may allow a worker to prevent adjacent jet assemblies from interfering with each other. 
     Similar to jet body  304 , jet body  404  includes two recesses  436  disposed on upstream portion  420  and configured to contain one or more O-rings  438 , such as those shown in  FIG. 20 . Recesses  436  may be configured such that the outside edge of the O-ring is flush with or extends slightly beyond the surface of the upstream portion of the jet body as shown in  FIG. 20 . As best seen in  FIG. 21 , jet back  402  also includes a spacing mechanism configured to ensure sufficient space between a proximate end  440  of upstream portion  420  of jet body  404  and an inner wall  442  of jet back  402 . In the example shown in  FIG. 21 , jet back  402  includes four spacers  444  disposed on inner wall  442  and formed as an integral part of jet back  402 . 
     In the embodiment shown in  FIGS. 20-21 , nozzle  408  is a structure formed as an integral part of jet back  402 . Nozzle  408  may include any suitable structure formed as part of jet back  402  and configured to change the direction and/or speed of the stream of water. As can best be seen in  FIG. 21 , inner wall  442  of jet back  402  includes a conical portion  446  narrowing to a first aperture  448 . Water ingress port  410  extends from a substantially cylindrical portion to a conical cavity  450  which tapers to first aperture  448 . In some examples, conical cavity  450  may be similar in shape to conical portion  348  of nozzle  308 . 
     Upstream portion  420  of jet body  404  includes a conical chamber  452 . Conical chamber  452  may be shaped to receive nozzle  408  of jet back  402 . In some examples, the shape of conical chamber  452  of jet body  404  may be substantially complementary to the shape of conical portion  446 . In some examples, the shape of conical chamber  452  may not be complementary to the shape of conical portion  446 . For example, conical chamber  452  may be significantly wider than conical portion  446  and may have a height that is equal to or greater than the height of conical portion  446 . A difference in size and shape between conical chamber  452  and conical portion  446  may be used to ensure that there is a space between conical portion  446  and conical chamber  452 . In the embodiment shown in  FIGS. 20-21 , spacers  444  are also included to ensure that there is space between conical portion  446  and conical chamber  452 . 
     In use, water passes through water ingress port  410 , through conical cavity  450  and first aperture  448 , and into the space between conical portion  446  and conical chamber  452 . Air ingress port  412  leads to the space between conical portion  446  and conical chamber  452 . The streams of air and water may merge in the space between conical portion  446  and conical chamber  452  and/or in conical chamber  452  before passing through second aperture  454 . Second aperture  454  connects conical chamber  452  with a receiving chamber. 
     The receiving chamber in jet body  404  is functionally substantially the same as receiving chamber  368  in jet body  304  and may be primarily disposed within downstream portion  422 . In this embodiment, the receiving chamber in jet body  404  includes a substantially cylindrical cavity. Similar to the first style of jet body  304 , jet body  404  further includes substantially rectangular protrusions disposed on an inner wall  460  of receiving chamber  456 . The protrusions may be used as a spacing mechanism to ensure sufficient space between a proximate end of the jet insert and the inner wall of the receiving chamber. Two hooks may be disposed inside of the receiving chamber. As in jet body  304 , the hooks may include an approximately U-shaped structure wherein one side is shorter than the other. This structure facilitates coupling with a jet insert. In some examples, jet body  404  may include any suitable number of hooks, which may include any suitable structure for engaging the jet insert. 
     As discussed with respect to jet assembly  300 , jet assembly  400  may include one or more versions of a jet insert, and a jet body  404 . For example, one or more different sizes and/or styles of jet body  404  may be configured to couple with a single style of jet back  402  and each of the one or more versions of jet body  404  may be configured to couple with one or more version of a jet insert. In other words, a variety of styles of jet body may be installed in multiple places on a hot tub  100  and different styles of jet insert may be coupled to each jet body depending on the location within the hot tub and the features of the jet body. In some examples, jet assembly  400  may include only one version of jet body  404  and/or only one version of a jet insert. 
     Only one size of jet body  404  is shown in the drawings. In the size of jet body  404  depicted in  FIG. 20 , the maximum diameter of downstream portion  422  is approximately 2.0 inches. Additionally, downstream portion  422  includes a flange  424  and a channel disposed on flange  424 . 
     In other sizes of jet body  404 , downstream portion  422  of jet body  404  may include any suitable maximum diameter. For example, the maximum diameter of downstream portion  422  may be between approximately 1.0 inches and approximately 5.0 inches. In some examples, four sizes of jet body may be used having maximum diameters of approximately 2.0 inches, approximately 3.0 inches, approximately 4.0 inches, and approximately 5.0 inches respectively. With the exception of the diameter of downstream portion  422  and certain features of the receiving chamber, each size of jet body  404  may be substantially identical. Features of the receiving chamber, such as the hooks, may differ between versions of jet body  404  to best couple and position a suitable version of the jet insert within each jet body. Each size of jet body  404  may be used and installed in hot tub body  104  in substantially the same way. Further, each style of jet body couples with jet back  402  in a substantially identical way. 
     During installation, jet assembly  400  may be assembled in multiple steps or at multiple stations. A first step may include coupling the air and water ingress ports of jet back  402  with tubing  120 . Coupling the air and water ingress ports of jet back  402  with tubing  120  may include any suitable process and/or structure. For example, tubing  120  may be slid over the ends of the air and water ingress ports of jet back  402  and a clamp (described in more detail below) may be used to prevent the tubing from sliding off. In some examples, a lubricant (e.g., soapy water) may be used to facilitate sliding the tubing over the ingress ports. In some examples, tubing  120  may include dual extrusion tubing. In some examples, tubing  120  may include separate air and water tubes which may be installed one at a time on the air and water ingress ports respectively. 
     Another step in assembling jet assembly  400  may include installing jet body  404  and a jet insert on hot tub shell  104 . For example, jet body  404  may be inserted into a hole formed in the shell of hot tub shell  104 . Jet body  404  may be inserted from the interior of hot tub shell  104  and may be secured to hot tub shell  104  by any suitable mechanism configured to be water tight and secure. For example, jet body  404  may attach to hot tub shell  104  via threaded engagement, glue, press-fitting, and/or any other suitable attachment mechanism. In some examples, attaching jet body  404  may include threading the jet body into the hot tub body and/or the use of a compressive gasket. A jet insert may be coupled to jet body  404  from the interior of hot tub shell  104  after jet body  404  has been installed in hot tub shell  104 . As discussed above, jet body  404  is configured to securely couple with and position a jet insert. In some examples, jet body  404  and/or a jet insert may be installed from the exterior of hot tub shell  104 . In some examples, jet body  404  and a jet insert may couple together through a hole in the hot tub shell, thereby attaching both parts to the hot tub shell. 
     Completing the installation of jet assembly  400  may include coupling jet back  402  (which is attached to tubing  120 ) to jet body  404  (which is attached to hot tub shell  104 ). Jet back  402  may be coupled with jet body  404  by a “press-and-click” method (described above). For example, jet back  402  and jet body  404  may be aligned and then compressed together to overcome the resistive force of spring biased clips  428 . In the embodiment shown in  FIGS. 20-21 , spring biased clips  428  are configured to flex outward, away from a default position (e.g., away from longitudinal axis  414 ), when sloped lip  434  slides over proximate end  440  of jet body  404  and along an external portion of upstream portion  420 . Spring biased clips  428  are further configured to snap back into the default position (e.g., back towards longitudinal axis  414 ) when sloped lip  434  encounters groove  430  of jet body  404 . Sloped lip  434  prevents spring biased clips  428 , and thus jet back  402 , from sliding towards proximate end  440  and off of jet body  404 . Thus, jet back  402  and jet body  404  are coupled together. 
     In some examples, jet back  402  and jet body  404  may be configured to be able to be unlocked and/or uncoupled. Uncoupling jet back  402  from jet body  404  may be accomplished by moving spring biased clips  428  away from jet body  404  (e.g., away from longitudinal axis  414 ) and sliding the jet back off of the jet body. In some examples, a worker may accomplish this using a finger to move the spring biased clips and/or using a tool. Releasably coupling the jet back and the jet body together may be advantageous as it may, among other advantages, allow a worker to uncouple a jet back that was coupled to the wrong jet body by mistake. 
     Each of the components of jet assembly  400  (e.g., jet back  402 , jet body  404 , and a jet insert) may be constructed out of any suitable material. For example, the components of jet assembly  400  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). The components of jet assembly  400  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     Third Straight Back Embodiment 
       FIG. 22  depicts a third embodiment  500  of straight back jet assembly  200 , which also includes a straight back jet back. The third embodiment of jet assembly  200  is generally indicated at  500  and includes a jet back  502 , a jet body  504 , and a jet insert (or jet face)  506 . A nozzle  508  includes a structure formed as an integral part of jet back  502 . Additionally, or alternatively, jet back  502  may be referred to as a straight back jet back or a straight jet back. Jet back  502  is an example of jet back  202  described above, jet body  504  is an example of jet body  204  described above, and jet insert  506  is an example of jet insert  206  described above. Many of the features of third embodiment  500  of jet assembly  200  are the same as in first embodiment  300 . Accordingly, similar components may be labeled with similar reference numbers and only an abbreviated discussion of such features will be provided here. The differences between the embodiments are described in detail below. 
       FIG. 22  depicts a sectional view of straight back jet assembly  500 , which includes straight back jet back  502 , jet body  504 , and jet insert  506 . As with jets  300  and jets  400 , jet back  502  includes two parallel ingress ports: a water ingress port  510  and an air ingress port  512 . Water ingress port  510  is substantially centered on a longitudinal axis  514  of the jet back and includes a lip or ridge  516 . Air ingress port  512  is parallel to water ingress port  510  and is offset from the center of jet back  502 . 
     In the embodiment shown in  FIG. 22 , jet back  502 —similar to jet backs  302  and  402 —is configured to couple with dual extrusion tubing having two parallel passages joined at a periphery (examples of dual extrusion tubing are discussed in more detail below). In some examples, jet back  502  may be configured to couple with any other suitable kind of tubing. Similar to jet backs  302  and  402 , jet back  502  further includes a central portion  518  configured to create a water tight seal with jet body  504 . Central portion  518  is in direct fluid communication with water ingress port  510  and air ingress port  512  and may include any suitable shape depending on the application and on the characteristics of the jet body. For example, central portion  518  may be substantially cylindrical as can be seen in  FIG. 22 . 
     As in the previous embodiments, jet body  504  includes an upstream portion  520  and a downstream portion  522  wherein the upstream portion is configured to be at least partially disposed within central portion  518  of jet back  502 . Jet back  502  includes an attachment mechanism extending from a first end  526  of central portion  518  and configured to attach the jet back to jet body  504  in a secure manner. The attachment mechanism, like the attachment mechanism for jet  300  and jet  400 , may include a plurality of spring biased clips  528  which are configured to couple with a retaining feature on the jet body (e.g., grooves  330  and  430  in jets  300  and  400  respectively). In some examples, spring biased clips  528  may include a resiliently flexible support  534  and a sloped lip  536  which is configured to couple with the retaining feature. In contrast with straight jets  300  and  400 , the retaining feature on jet body  504  takes the form of a ridge  530 . In some examples, multiple ridges  530  may be used, forming an adjustable retainer  532 . Ridges  530  may be disposed on any suitable portion of jet body  504 , for example, on upstream portion  520 . 
     In some examples, the attachment mechanism may be configured to couple jet back  502  to jet body  504  while allowing jet back  502  to rotate relative to jet body  504 . In other words, in some examples, jet back  502  may able to rotate about longitudinal axis  514  when coupled to jet body  504  while maintaining a water- and air-tight seal; this may allow a worker to prevent adjacent jet assemblies from interfering with each other. 
     Similar to jet bodies  304  and  404 , jet body  504  includes two recesses  538  configured to contain one or more O-rings  540 , such as those shown in  FIG. 22 . Recesses  538  may be configured such that the outside edge of the O-ring is flush with or extends slightly beyond the surface of the upstream portion of the jet body. Unlike jet backs  302  and  402 , jet back  502  does not include a spacing mechanism to create space between a proximate end  542  of upstream portion  520  of jet body  504  and an inner wall  544  of jet back  502 . Instead, when jet assembly  500  is assembled, proximate end  542  of the jet body is flush with inner wall  544 . 
     Nozzle  508  may include any suitable structure configured to change the direction and/or speed of the stream of water. In the embodiment of straight jet  500  shown in  FIG. 22 , as in straight jet  400 , nozzle  508  is a structure formed as an integral part of jet back  502  and jet body  504  is shaped to receive the conical portion of jet back  502 . Conical portion  552 , first aperture  554 , conical cavity  556 , conical chamber  558 , and second aperture  562  of straight jet  500  are substantially the same as the corresponding features of straight jet  400 . As can be seen in  FIG. 22 , inner wall  544  of jet back  502  includes a substantially conical portion  552  narrowing to a first aperture  554 . As in jet  400 , water ingress port  510  extends from a substantially cylindrical portion to a conical cavity  556  which tapers to first aperture  554 . 
     Upstream portion  520  of jet body  504 , like upstream portion  520  of jet body  404 , includes a conical chamber  558  shaped to receive nozzle  508  of jet back  502 . In some examples, the shape of conical chamber  558  of jet body  504  may be substantially complementary to the shape of conical portion  552 . In some examples, the shape of conical chamber  558  may not be complementary to the shape of conical portion  552 . For example, conical chamber  558  may be significantly wider than conical portion  552  and may have a height that is equal to or greater than the height of conical portion  552 . A difference in size and shape between conical chamber  558  and conical portion  552  may be used to ensure that there is a space  562  between conical portion  552  and conical chamber  558  even when proximate end  542  of the jet body is flush with inner wall  544 . 
     In use, water passes through water ingress port  510 , through conical cavity  556  and first aperture  554 , and into space  562  between conical portion  552  and conical chamber  558 . Air ingress port  512  also leads to space  562 . The streams of air and water may merge in space  562  between conical portion  552  and conical chamber  558  and/or in conical chamber  558  before passing through a second aperture  562 . Second aperture  562  connects conical chamber  558  with receiving chamber  546 . 
       FIG. 22  shows the jet body of the current embodiment. Second aperture  562  connects conical chamber  558  with receiving chamber  546 . Receiving chamber  546  in jet body  504  is substantially the same as the receiving chamber in jet bodies  304  and  404  and may be primarily disposed within downstream portion  522 . In this embodiment, receiving chamber  546  includes a substantially cylindrical cavity as shown in  FIG. 22 . Similar to the first style of jet body  304 , jet body  504  further includes two hooks  548  disposed inside of receiving chamber  546  which facilitate coupling with jet insert  506 . In some examples, jet body  504  may include any suitable number of hooks  548 , which may include any suitable structure for engaging jet insert  506 . 
     A jet insert  506  is also shown in  FIG. 22 . Jet insert  506  may include teeth  550  configured to engage with hooks  548 . For example, to couple jet insert  506  to jet body  504 , jet insert  506  may be inserted into the receiving cavity such that hooks  548  and teeth  550  are offset and rotated until the hooks and teeth engage. In some examples, jet insert  506  may include any suitable number of teeth  550 . 
     Jet insert  506  may include any suitable structure configured to pass the mixture of air and water to the interior of hot tub shell  104  and/or to manipulate the speed, direction, and/or other properties of the stream of air and water. For example, jet insert  506  includes a flow director  564 . Flow director  564  may be visible to a user from inside hot tub shell  104 . Flow director  564  may include any suitable structure configured to manipulate the speed and direction of the stream of air and water depending on the application and the characteristics of jet body  504 , hot tub shell  104 , and jet insert  506 . For example, flow director  564  may include a substantially cylindrical portion. In some examples, jet insert  506  and/or flow director  564  may include decorative portions and/or may include any suitable structures and/or shapes to match an aesthetic. 
     As discussed with respect to jet assembly  300  and  400 , jet assembly  500  may include, or be compatible with, one or more versions of jet insert  506  and jet body  404 . For example, one or more different sizes and/or styles of jet body  504  may be configured to couple with a single style of jet back  502  and each of the one or more versions of jet body  504  may be configured to couple with one or more versions of jet insert  506 . In other words, a variety of styles of jet body may be installed in multiple places on a hot tub  100  and different styles of jet insert may be coupled to each jet body depending on the location within the hot tub and the features of the jet body. In some examples, jet assembly  500  may include only one version of jet body  504  and/or only one version of jet insert  506 . 
     Only one size of jet body  504  is shown in the drawings. In the size of jet body  504  depicted in  FIG. 22 , the maximum diameter of downstream portion  522  is approximately 2.0 inches. Additionally, downstream portion  522  includes a flange  524  and jet insert  506  includes a curved flange  566  which overlaps with flange  524 . In other sizes of jet body  504 , downstream portion  522  of jet body  504  may include any suitable maximum diameter. For example, the maximum diameter of downstream portion  522  may be between approximately 1.0 inches and approximately 5.0 inches. In some examples, four sizes of jet body may be used having maximum diameters of approximately 2.0 inches, approximately 3.0 inches, approximately 4.0 inches, and approximately 5.0 inches respectively. 
     With the exception of the diameter of downstream portion and certain feature of receiving chamber  546 , each size of jet body  504  may be substantially identical. Feature of receiving chamber  546 , such as hooks  548 , may differ between versions of jet body  504  to best couple and position a suitable version of jet insert  506  within each jet body. Each size of jet body  504  may be used and installed in hot tub shell  104  in substantially the same way. Further, each style of jet body couples with jet back  502  in a substantially identical way. 
     During installation, jet assembly  500  may be assembled in multiple steps or at multiple stations. A first step may include coupling the air and water ingress ports of jet back  502  with tubing  120 . Coupling the air and water ingress ports of jet back  502  with tubing  120  may include any suitable process and/or structure. For example, tubing  120  may be slid over the ends of the air and water ingress ports of jet back  502  and a clamp (described in more detail below) may be used to prevent the tubing from sliding off. In some examples, a lubricant (e.g., soapy water) may be used to facilitate sliding the tubing over the ingress ports. In some examples, tubing  120  may include dual extrusion tubing. In some examples, tubing  120  may include separate air and water tubes which may be installed one at a time on the air and water ingress ports respectively. 
     Another step in installing jet assembly  500  may include installing jet body  504  and jet insert  506  on hot tub shell  104 . For example, jet body  504  may be inserted into a hole formed in the shell of hot tub shell  104 . Jet body  504  is inserted from the interior of hot tub shell  104  and may be secured to hot tub shell  104  by any suitable mechanism configured to be water tight and secure. For example, jet body  504  may attach to hot tub shell  104  via threaded engagement, glue, press-fitting, and/or any other suitable attachment mechanism. In some examples, attaching jet body  504  may include threading the jet body into the hot tub body and/or the use of a compressive gasket. Jet insert  506  may be coupled to jet body  504  from the interior of hot tub shell  104  after jet body  504  has been installed in hot tub shell  104 . As discussed above, jet body  504  is configured to securely couple with and position jet insert  506 . 
     A further step in the installation of jet assembly  500  may include coupling jet back  502  (which may already be attached to tubing  120 ) to jet body  504  (which may already be attached to hot tub shell  104 ). Jet back  502  may be coupled with jet body  504  by a “press-and-click” method (described above). For example, jet back  502  and jet body  504  may be aligned and then compressed together to overcome the resistive force of spring biased clips  528 . In the embodiment shown in  FIG. 22 , spring biased clips  528  are configured to flex outward, away from a default position (e.g., away from longitudinal axis  514 ), when sloped lip  536  slides over a leading edge of a first one of ridges  530  on jet body  504 . Spring biased clips  528  are further configured to snap back into the default position (e.g., back towards longitudinal axis  514 ) when sloped lip  536  passes the first one of ridges  530  on jet body  504 . If jet back  502  and jet body  504  continue to be compressed together, spring biased clips  528  may similarly snap over a second one of ridges  530  on jet body  504 . Once past at least one of ridges  530 , sloped lip  536  engages with at least one of ridges  530  and prevents spring biased clips  528 , and thus jet back  502 , from sliding towards proximate end  542  and off of jet  502 . Thus, jet back  502  and jet body  504  are coupled together. Using multiple ridges  530  to form adjustable retainer  532  may, among other advantages, allow a worker to control how tightly the jet back and the jet body are coupled. 
     In some examples, jet back  502  and jet body  504  may be configured to be able to be unlocked and/or uncoupled. Uncoupling jet back  502  from jet body  504  may be accomplished by moving spring biased clips  528  away from jet body  504  (e.g., away from longitudinal axis  514 ) and sliding the jet back off of the jet body. In some examples, a worker may accomplish this using a finger to move the spring biased clips and/or using a tool. Releasably coupling the jet back and the jet body together may be advantageous as it may, among other advantages, allow a worker to uncouple a jet back that was coupled to the wrong jet body by mistake, or to replace a defective or broken jet back. 
     Each of the components of jet assembly  500  (e.g., jet back  502 , jet body  504 , and jet insert  506 ) may be constructed out of any suitable material. For example, the components of jet assembly  500  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). The components of jet assembly  500  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     Angled Back Jet Back Overview 
     In some situations, a jet assembly  200  may be disposed in a region of hot tub  100  where the space between hot tub shell  104  and hot tub frame  102  is too small to allow a straight back jet back (such as jet backs  302 ,  402 , or  502 ) to fit between hot tub shell  104  and hot tub frame  102  while coupled to jet body  204  and tubing  120 . For example, if the distance between hot tub shell  104  and hot tub frame  102  is too small, tubing  120  may be forced to bend sharply immediately past the ends of the air and water ingress ports; this may compromise the integrity of the plumbing system by damaging the seal between tubing  120  and jet back  202 , damaging tubing  120 , and/or impeding the flow of water and/or air through tubing  120  and jet back  202 . In some examples, there may not be space for a straight back jet back to couple to jet body  204  even when not coupled to tubing  120 . 
     To avoid this issue, the present disclosure teaches embodiments of jet back  202  which include a water ingress port and an air ingress port which are oriented at an angle with respect to the longitudinal axis of the jet back. Such an angled jet back may extend out from hot tub shell a shorter distance when coupled to a jet body than a straight back jet back (such as jet backs  302 ,  402 , and  502  described above) and therefore may fit in areas of hot tub  100  where a straight jet back might not, for example, in places where there is a small distance between hot tub shell  104  and hot tub frame  102 . Additionally, or alternatively, the angled jet back may allow tubing  120  to extend in a direction substantially parallel to hot tub shell  104  and/or may avoid forcing tubing  120  to bend at a sharp angle after extending past the jet back. 
     Possible disadvantages to the use of an angled back jet back can include increased levels of noise produced by the jet and increased resistance to the flow of water through the jet back. Using angled back jet backs can also clutter the area right next to the hot tub shell, since the first few inches of tubing are positioned right next to hot tub shell  104  instead of immediately extending away from the hot tub shell. This clutter can be an issue in areas where there are many jets as it may obscure uncoupled jet bodies and/or increase the likelihood of mistakes. Using a combination of straight back and angled back jet backs can substantially avoid the issues associated with both types of jet backs. Using straight back jet backs such as jet backs  302 ,  402 , or  502  in most instances avoids crowding and noise issues. Using angled back jet backs in areas with little space between hot tub shell  104  and hot tub frame  102  avoids spacing issues. Selective use of angled back jet backs may limit the extra noise produced while allowing the jet back to fit in smaller spaces. 
     As shown in  FIGS. 23-30 , this section describes three embodiments of an angled back jet assembly. Additionally, or alternatively, an angled back jet assembly may be referred to as an angled back jet, an angled jet, an angled jet assembly, and/or a jet. When only the word jet (or the phrase jet assembly) is used, the context indicates whether a straight back jet assembly or an angled back jet assembly is meant. The angled jets described below are substantially similar to the straight back jets described above, except that the water ingress port and the air ingress port of the jet back are oriented at an angle (for example, 90 degrees) with respect to a central portion of the jet back. While this section includes a description of three possible embodiments of an angled back jet assembly, a person of ordinary skill in the art will recognize that other embodiments or variations are possible. 
     First Angled Back Embodiment 
       FIGS. 23 through 27  depict a fourth embodiment  600  of jet assembly  200 , which includes an angled back jet back. The fourth embodiment of jet assembly  200  is generally indicated at  600  and includes an angled jet back  602 , a jet body  604 , and a nozzle  608 . In some cases, jet assembly  600  also may include a jet insert (not shown). Additionally, or alternatively, jet assembly  600  may be referred to as a jet, a jet assembly, an angled jet, an angled jet assembly, an angled back jet, and/or an angled back jet assembly. Additionally, or alternatively, jet back  602  may be referred to as an angled back jet back or an angled jet back. 
     Jet back  602  is an example of jet back  202  generally described above, jet body  604  is an example of jet body  204  generally described above, and a suitable jet insert is an example of jet insert  206  generally described above. Jet body  604  and nozzle  608  of angled jet  600  are substantially similar to jet body  304  and nozzle  308 , respectively, of jet  300 . Accordingly, similar components and/or features may be labeled with similar reference numbers and only an abbreviated discussion of such features will be provided here. Duplicate drawings are not provided for components which are substantially identical to other embodiments of jet assembly  200 . 
     The primary difference between angled jet assembly  600  and straight back jet assembly  300  is the shape of angled jet back  602  compared with jet back  302 . Whereas jet back  302  includes air and water ingress ports which are parallel to a longitudinal axis of the jet back, angled jet back  602  includes air and water ingress ports which are not parallel to a longitudinal axis of the jet back. Accordingly, some of the components and features of angled jet assembly  600  are substantially similar to or the same as some of the components and features of straight jet assembly  300 . Accordingly, similar components may be labeled with similar reference numbers and only an abbreviated discussion of such features will be provided here. The differences between the embodiments are described in detail below and new features will be given new reference numbers. 
       FIGS. 23-27  show various views of angled back jet  600  and components thereof.  FIGS. 10-13  show various views of jet body  304  and nozzle  308  (which are substantially similar to jet body  604  and nozzle  608 , respectively) suitable for use with jet back  602  to form jet assembly  600 .  FIG. 23  shows an exploded sectional view of angled jet  600  and includes illustrative embodiments of angled jet back  602 , jet body  604 , and nozzle  608 .  FIG. 24  depicts a partially assembled view of angled jet assembly  600  in which nozzle  608  is press fit into jet body  604 .  FIG. 25  depicts a fully assembled view of angled jet  600 .  FIG. 26  is a sectional view of a fully assembled angled back jet assembly  600  and depicts how the components of angled jet assembly  600  fit together.  FIG. 27  is a front isometric view of angled jet back  602 .  FIG. 10  is a side isometric view of nozzle  608  ( 308 ) and  FIG. 11  is a back isometric view of nozzle  608  ( 308 ).  FIG. 12  depicts nozzle  608  ( 308 ) press fit into jet body  604  ( 304 ) and the O-rings installed on jet body  604  ( 304 ).  FIG. 13  is a front isometric view of jet body  604  ( 304 ). 
     The jet insert for jet assembly  600  may be substantially identical to the jet insert for jet assembly  300 . Note that  FIGS. 23-27 and 10-13  do not show a jet insert, however, as discussed, jet body  604  ( 304 ) is configured to couple with a jet insert. As seen in  FIG. 23 , angled back jet assembly  600  includes angled jet back  602 , nozzle  608  ( 308 ), jet body  604  ( 304 ), and also may include a jet insert (not shown). Jet back  602  is substantially similar to jet back  302 ; the primary difference between jet back  302  and jet back  602  is the configuration of the air and water ingress ports. 
     Jet back  602  includes two ingress ports: a water ingress port  610  and an air ingress port  612 . Water ingress port  610  is larger in diameter than air ingress port  612  and at least a portion of water ingress port  610  is parallel air ingress port  612 . In the embodiment shown in  FIGS. 23-27 , water ingress port  610  includes a base portion  616  and an extended portion  618 . Base portion  616  is substantially centered on longitudinal axis  614  of the jet back and is substantially parallel with longitudinal axis  614 . Extended portion  618  may be oriented at any suitable angle relative to base portion  616 . In the embodiment shown in  FIGS. 23-27 , extended portion  618  is oriented at an approximately 90-degree angle with respect to base portion  616 . Additionally, or alternatively, water ingress port  610  may be referred to as a water barb, an angled water ingress port, or an angled water barb. Similar to water ingress port  310 , water ingress port  610  includes a lip or ridge  620  as can best be seen in  FIGS. 24 and 25 . Lip  620  may include any suitable structure configured to ensure a water tight seal between water ingress port  610  and a length of tubing (such as tubing  120 ). For example, lip  620  may include a sloped ridge as in  FIGS. 23-26 . 
     Air ingress port  612  is substantially parallel with extended portion  618  of the water ingress port, and may be offset from the center of jet back  602 . Air ingress port  612  may form substantially the same angle with longitudinal axis  614  as extended portion  618 . For example, air ingress port  612  may form an approximately 90-degree angle with longitudinal axis  614 . In some examples, air ingress port  612  may extend from the side of jet back  602 . Additionally, or alternatively, air ingress port  612  may be referred to as an air barb, an angled air barb, or an angled air ingress port. In some examples, air ingress port  612  may include a lip or other feature to ensure a seal. In some examples, an external portion of air ingress port  612  may be smooth as can best be seen in  FIGS. 23-26 . 
     In the embodiment shown in  FIGS. 23-27 , jet back  602  is, like jet back  302 , configured to couple with dual extrusion tubing having two parallel passages joined at a periphery (examples of dual extrusion tubing are discussed below). In some examples, jet back  602  may be configured to couple with any other suitable kind of tubing. For example, jet back  602  may be configured to couple with two separate lengths of tubing, one which carries air and one which carries water. In some examples, configuring jet back  602  to couple with different kinds of tubing may include changing the spacing between the air and water ingress ports and/or the dimensions for the air and water ingress ports. 
     As with previous embodiments, jet back  602  further includes a central portion  622  configured to create a water tight seal with jet body  604 . Central portion  622  is in direct fluid communication with water ingress port  610  and air ingress port  612  and may include any suitable shape depending on the application and on the characteristics of the jet body. For example, central portion  622  may be substantially cylindrical as can best be seen in  FIGS. 24, 25, and 27 . In some examples, central portion  622  may be substantially rectangular or substantially triangular. 
     Jet body  604  is substantially identical to jet body  304 . Accordingly, only an abbreviated description will be given here. Jet body  604  includes an upstream portion  624  and a downstream portion  626 . Upstream portion  624  may include any suitable structure configured to be at least partially disposed within central portion  622 . For example, upstream portion  624  may be substantially cylindrical. Like jet back  302 , jet back  602  includes an attachment mechanism which extends from a first end  630  of central portion  622  and which is configured to attach the jet back to jet body  604  in a secure manner. The attachment mechanism, like the attachment mechanism for jet  300 , includes a plurality of spring biased clips  632  which are configured to couple with a retaining feature, such as a groove  634 , on jet body  604 . In the embodiment shown in  FIGS. 23-27 , jet back  602  includes four spring biased clips  632  (as best seen in  FIG. 27 ). In some examples, spring biased clips  632  may include a resiliently flexible support  636  and a sloped lip  638  which is configured to engage with groove  634 . 
     In some examples, the attachment mechanism may be configured to couple jet back  602  to jet body  604  while allowing jet back  602  to rotate relative to jet body  604 . In other words, in some examples, jet back  602  may be able to rotate about longitudinal axis  614  when coupled to jet body  604  while maintaining a water- and air-tight seal; this may allow a worker to prevent adjacent jet assemblies from interfering with each other. 
     Like jet body  304 , jet body  604  includes two recesses  640  disposed on upstream portion  624  and configured to contain two O-rings  642  such as those shown in  FIGS. 12 and 13 . Recesses  640  may be configured such that the outside edge of the O-ring is flush with or extends slightly beyond the surface of the upstream portion of the jet body as shown in  FIG. 24 . As best seen in  FIG. 27 , jet back  602  also includes a spacing mechanism configured to ensure sufficient space between a proximate end  644  of upstream portion  624  of jet body  604  and an inner wall  646  of jet back  602 . The spacing mechanism may be substantially identical to the spacing mechanism for jet  300 . For example, a plurality of spacers  648  may be disposed on inner wall  646  and configured to prevent proximate end  644  of the jet body from becoming flush with inner wall  646 . In the example shown in  FIG. 27 , jet back  602  includes four spacers  648  disposed on inner wall  646  and formed as an integral part of jet back  602 . 
     Nozzle  608  is substantially identical to nozzle  308 . Accordingly, only an abbreviated description will be given here. Nozzle  608 , like nozzle  308 , is formed as a separate piece from the jet back and the jet body and is configured to be press fit into the jet body. Nozzle  608  includes a main body  650  and a conical portion  652 . Main body  650  may include a hollow, substantially cylindrical tube as best seen in  FIGS. 10-11 . For example, conical portion  652  may taper from a larger, round first aperture  654  to a smaller, round second aperture  656  as best seen in  FIG. 11 . As in nozzle  308 , conical portion  652  of nozzle  608  includes a constant-diameter, annular flange  658  attached to first aperture  654 . Nozzle  608  further includes four substantially rectangular support structures  660 , as can be seen in  FIGS. 10-11 . 
     Nozzle  608  is configured to be press-fit into jet body  604 . As shown in  FIGS. 24, 26, and 12 , main body  650  is configured to fit at least partially within a main cavity  662  of jet body  604  and conical portion  652  is configured to fit within a recessed portion  664  of inner wall  646  when jet back  602  is coupled with jet body  604 . For example, an outer diameter of main body  650  may be very close to the inner diameter of main cavity  662  to ensure a secure fit. In some examples, main body  650  may have a slight taper to create a wedge fit between nozzle  608  and main cavity  662 . Support structures  660  may be configured to leave gaps  666  between the conical portion  652 , main body  650 , and support structures  660  (see, e.g.,  FIG. 11 ). When jet back  602  is coupled to jet body  604 , water from water ingress port  610  may be passed through first aperture  654  and second aperture  656  while air from air ingress port  612  may be passed into an air chamber  668  and through gaps  666 . The air and water may mix in main cavity  662  of the jet body and/or within the main body  650  of the nozzle before passing through a main aperture  670  of the jet body. 
     Jet body  604  is substantially identical to jet body  304 . Accordingly,  FIGS. 12 and 13  also show the jet body of the current embodiment. Main aperture  670  connects main cavity  662  with a receiving chamber  672 . Receiving chamber  672  is primarily disposed within downstream portion  626  and may include any suitable structure for receiving at least a portion of a jet insert. For example, receiving chamber  672  may include a substantially cylindrical cavity as shown in  FIGS. 12 and 13 . A plurality of hooks  674  are disposed inside of receiving chamber  672 . In the embodiment shown in  FIG. 13 , hooks  674  include an approximately U-shaped structure wherein one side is shorter than the other. A jet insert having similarly shaped teeth may be inserted into the receiving cavity such that the hooks and teeth are offset and rotated until the hooks and teeth engage. Jet body  604  may include any suitable number of hooks  674 . For example, the embodiment shown in  FIG. 13  includes two hooks  674 . In some examples, receiving chamber  672  may include any suitable structures for coupling to and suitably positioning a jet insert. 
     The jet insert for jet assembly  600  is substantially identical to the jet insert for jet assembly  300  and may include any suitable structure configured to pass the mixture of air and water to the interior of hot tub shell  104 . In some examples, some or all of the jet insert may be visible from the interior of hot tub body  104  and/or the jet insert may include decorative portions. In some examples, the jet insert may include any suitable structures configured to manipulate the speed, direction, and/or other properties of the stream of air and water. For example, the jet insert may include a flow director and/or a rotating nozzle. 
     Similar to jet assembly  300 , jet assembly  600  may include multiple versions of the jet insert. For example, a plurality of different jet inserts may be configured to couple with jet body  604 . In other words, the same style of jet body may be installed in multiple places on a hot tub  100  and different styles of jet insert may be coupled to each jet body depending on the location within the hot tub and desired application. 
     Additionally, or alternatively, jet assembly  600 , like jet assembly  300 , may include multiple versions of jet body  604 . For example, a plurality of different sizes and/or styles of jet body  604  may be configured to couple with a single style of jet back  602 . Each version of jet body  604  may be configured to couple with one or more versions of the jet insert. In other words, a variety of styles of jet body may be installed in multiple places on a hot tub  100  and different styles of jet insert may be coupled to each jet body depending on the location within the hot tub and the features of the jet body. 
     As discussed above with respect to jet  300 ,  FIGS. 12-13  depict a first style of jet body  604  (which, as discussed, is substantially identical to jet body  304 ) and  FIGS. 14-19  depict three other styles of jet body  604  ( 304 ) indicated at  304   a ,  304   b , and  304   c  respectively, which are suitable for use with jet assembly  600 . As discussed above, many aspects of jet bodies  304   a ,  304   b , and  304   c  are substantially similar to jet body  604  ( 304 ). Accordingly, similar features will be denoted with similar reference numbers and will not be discussed here. Features of receiving chamber  672  ( 368 ), such as hooks  674  ( 370 ), may differ between jet bodies  304 ,  304   a ,  304   b , and  304   c  to best couple and position a suitable version of the jet insert within each jet body. Jet body  604  ( 304 ) and the jet insert may be coupled together using hooks, clips, threaded engagement, and/or any other suitable method. 
     As discussed above, downstream portion  626  of jet body  604  ( 304 ) has a maximum diameter of approximately 1.9 inches. Jet body  604  ( 304 ) includes two substantially rectangular protrusions  678  disposed on an inner wall  676  of receiving chamber  672 . Protrusions  678  may be used as a spacing mechanism to ensure sufficient space between a proximate end of the jet insert and inner wall  676  of receiving chamber  672 . Additionally, flange  628  on downstream portion  626  includes a channel  680 . 
     Jet body  304   a  is shown in  FIGS. 14-15  and includes a downstream portion  626  having a maximum diameter of approximately 2.7 inches. Jet body  304   a  includes two hooks, an annular flange disposed adjacent a main aperture, and two slots disposed on the flange. The annular flange and the slots may be configured to facilitate coupling with and positioning the jet insert in conjunction with the hooks. 
       FIGS. 16 and 17  show jet body  304   b . Jet body  304   b  includes a downstream portion having a maximum diameter of approximately 3.2 inches. Jet body  304   b  includes four hooks and a flange which includes a channel and four slots disposed within the channel. 
       FIGS. 18 and 19  show jet body  304   c . Jet body  304   c  includes a downstream portion having a maximum diameter of approximately 4.5 inches. Jet body  304   c  includes a flange and four spring biased clips configured to engage with a suitable style of jet insert. As discussed with respect to jet assembly  300 , each of jet body  304 , jet body  304   a , jet body  304   b , and jet body  304   c  may be used and installed in hot tub body  104  in substantially the same way. Further, each style of jet body couples with nozzle  608  ( 308 ) and jet back  602  in a substantially identical way. 
     During installation, jet assembly  600  may be assembled in substantially the same steps and/or at substantially the same stations as jet assembly  300 . A first step may include press fitting nozzle  608  into main cavity  662  of jet body  604  (see  FIG. 12 ) and coupling the air and water ingress ports of jet back  602  with tubing  120 . In some examples, press-fitting nozzle  608  into main cavity  662  may include using a lubricant (for example, soapy water) or an adhesive. Coupling the air and water ingress ports of jet back  602  with tubing  120  may include any suitable process and/or structure. For example, tubing  120  may be slid over the ends of the air and water ingress ports of jet back  602  and a clamp (described in more detail below) may be used to prevent the tubing from sliding off. In some examples, a lubricant (e.g., soapy water) may be used to facilitate sliding the tubing over the ingress ports. Tubing  120  may include dual extrusion tubing and/or separate air and water tubes which may be installed one at a time on the air and water ingress ports respectively. 
     Another step in assembling jet assembly  600  may include installing jet body  604  and a jet insert in hot tub shell  104 . For example, jet body  604  (with nozzle  608 ) may be inserted into a hole formed in the shell of hot tub shell  104 . Jet body  604  may be inserted from the interior of hot tub shell  104  and may be secured to hot tub shell  104  by any suitable mechanism configured to be water tight and secure. For example, jet body  604  may attach to hot tub shell  104  via threaded engagement, glue, press-fitting, and/or any other suitable attachment mechanism. 
     In some examples, attaching jet body  604  may include threading the jet body into the hot tub body and/or the use of a compressive gasket. A jet insert may be coupled to jet body  604   d  from the interior of hot tub shell  104  after jet body  604  has been installed in hot tub shell  104 . As discussed above, jet body  604  is configured to securely couple with and position the jet insert. In some examples, jet body  604  and/or a compatible jet insert may be installed from the exterior of hot tub shell  104 . In some examples, jet body  604  and a compatible jet insert may couple together through a hole in the hot tub shell, thereby attaching both parts to the hot tub shell. 
     Completing the installation of jet assembly  600  may include coupling jet back  602  (which is attached to tubing  120 ) to jet body  604  (which is attached to hot tub shell  104  and includes nozzle  608 ). Jet back  602  may be coupled with jet body  604  by a “press-and-click”method (described above). For example, jet back  602  and jet body  604  may be aligned and then compressed together to overcome the resistive force of spring biased clips  632 . In the embodiment shown in  FIGS. 23-27 , spring biased clips  632  are configured to flex outward, away from a default position (e.g., away from longitudinal axis  614 ), when sloped lip  638  slides over proximate end  644  of jet body  604  and along an external portion of upstream portion  624 . Spring biased clips  632  are further configured to snap back into the default position (e.g., back towards longitudinal axis  614 ) when sloped lip  638  encounters groove  634  of jet body  604 . Sloped lip  638  prevents spring biased clips  632 , and thus jet back  602 , from sliding towards proximate end  644  and off of jet  602 . Thus, jet back  602  and jet body  604  are coupled together. 
     In some examples, jet back  602  and jet body  604  may be configured to be able to be unlocked and/or uncoupled. Uncoupling jet back  602  from jet body  604  may be accomplished by moving spring biased clips  632  away from jet body  604  (e.g., away from longitudinal axis  614 ) and sliding the jet back off of the jet body. In some examples, a worker may accomplish this using a finger to move the spring biased clips and/or using a tool. Releasably coupling the jet back and the jet body together may be advantageous as it may, among other advantages, allow a worker to uncouple a jet back that was coupled to the wrong jet body by mistake. 
     Each of the components of jet assembly  600  (e.g., jet back  602 , jet body  604 , a suitable jet insert, and nozzle  608 ) may be constructed out of any suitable material. For example, the components of jet assembly  600  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). The components of jet assembly  600  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     Second Angled Back Embodiment 
       FIGS. 28-29  depict a fifth embodiment  700  of a jet assembly, which also includes an angled back jet back. The fifth jet assembly embodiment is generally indicated at  700  and includes an angled jet back  702 , a jet body  704 , and a jet insert (not shown). A nozzle  708  includes a structure formed as an integral part of jet back  702 . Jet back  702  is an example of jet back  202  described above, jet body  704  is an example of jet back  204  described above, and a suitable jet insert is an example of jet insert  206  described above. Additionally, or alternatively, jet assembly  700  may be referred to as a jet, a jet assembly, an angled jet, an angled jet assembly, an angled back jet, and/or an angled back jet assembly. Additionally, or alternatively, jet back  702  may be referred to as an angled back jet back or an angled jet back. Additionally, or alternatively, the jet insert may be referred to as a jet face. 
     Many of the features of fifth embodiment  700  of jet assembly  200  are the same as second embodiment  400 . The primary difference between angled jet assembly  700  and straight back jet assembly  400 , is the shape of angled jet back  702  compared with jet back  402 . Whereas jet back  402  includes air and water ingress ports which are parallel to a longitudinal axis of the jet back, angled jet back  702  includes air and water ingress ports which are not parallel to a longitudinal axis of the jet back. Accordingly, jet body  704  and nozzle  708  of angled jet  700  are substantially identical to jet body  404  and nozzle  408  of jet  400 . Accordingly, similar components and/or features may be labeled with similar reference numbers and only an abbreviated discussion of such features will be provided here. Duplicate drawings are not provided for components which are substantially identical to other embodiments of jet assembly  200 . The differences between the embodiments are described in detail below. 
       FIGS. 28-29  show various views of angled back jet  700  and components thereof.  FIG. 28  depicts a partially exploded isometric view of angled back jet assembly  700  and includes illustrative embodiments of angled jet back  702  and jet body  704 . Jet body  704  is substantially identical to jet body  404 .  FIG. 29  is a front isometric view of angled jet back  702 . The jet insert for jet assembly  700  may be substantially identical to the jet insert for jet assembly  400 . Note that  FIGS. 28-29  do not show a jet insert, however, as discussed, jet body  704  is configured to couple with a compatible jet insert. 
     As seen in  FIG. 28 , angled back jet assembly  700  includes angled jet back  702 , nozzle  708  ( 408 ), jet body  704  ( 404 ), and a jet insert (not shown). Jet body  704  and nozzle  708  are substantially identical to jet body  404  and nozzle  408  respectively. Jet back  702  is substantially similar to jet back  402 ; the primary difference between jet back  402  and angled jet back  702  is the configuration of the air and water ingress ports. Specifically, the air and water ingress ports extend at an angle with respect to the longitudinal axis of the jet back. The air and water ingress ports of jet back  702  are substantially similar to the air and water ingress ports of jet back  602 . 
     Jet back  702  includes two ingress ports: a water ingress port  710  and an air ingress port  712 . Water ingress port  710  is larger in diameter than air ingress port  712  and at least a portion of water ingress port  710  is parallel to air ingress port  712 . In the embodiment shown in  FIGS. 28-29 , water ingress port  710  includes a base portion  716  and an extended portion  718 . Base portion  716  is substantially centered on longitudinal axis  714  of the jet back and is substantially parallel with longitudinal axis  714 . Extended portion  718  may be oriented at any suitable angle relative to base portion  716 . In the embodiment shown in  FIGS. 28-29 , extended portion  718  is oriented at an approximately 90-degree angle with respect to base portion  716 . Additionally, or alternatively, water ingress port  710  may be referred to as a water barb, an angled water ingress port, or an angled water barb. Similar to water ingress port  410 , water ingress port  710  includes a lip or ridge  720  as can best be seen in  FIGS. 28 and 29 . For example, lip  720  may include a sloped ridge configured to ensure a water tight seal between water ingress port  710  and a length of tubing (such as tubing  120 ). 
     Air ingress port  712  is substantially parallel with extended portion  718  and may be offset from the center of jet back  702 . Air ingress port  712  may form substantially the same angle with longitudinal axis  714  as extended portion  718 . For example, air ingress port  712  may form an approximately 90-degree angle with longitudinal axis  714 . In some examples, air ingress port  712  may extend from the side of jet back  702 . Additionally, or alternatively, air ingress port  712  may be referred to as an air barb, an angled air barb, or an angled air ingress port. An external portion of air ingress port  712  may be smooth as can best be seen in  FIGS. 28-29 . 
     In the embodiment shown in  FIGS. 28-29 , jet back  702 —similar to jet back  402 —is configured to couple with dual extrusion tubing having two parallel passages joined at a periphery (examples of dual extrusion tubing are discussed in more detail below). In some examples, jet back  702  may be configured to couple with any other suitable kind of tubing. Similar to jet back  402 , jet back  702  further includes a central portion  722  configured to create a water tight seal with jet body  704  ( 404 ). Central portion  722  is in direct fluid communication with water ingress port  710  and air ingress port  712  and may include any suitable shape depending on the application and on the characteristics of the jet body. In this embodiment, central portion  722  is substantially cylindrical as can be seen in  FIGS. 28-29 . 
     As in previous embodiments, jet body  704  ( 404 ) includes an upstream portion  724  and a downstream portion  726  wherein the upstream portion is configured to be at least partially disposed within central portion  722  of jet back  702 . Jet back  702  includes an attachment mechanism extending from a first end  730  of central portion  722  and configured to couple the jet back to jet body  704  ( 404 ) in a secure manner. The attachment mechanism, like the attachment mechanism for jet  400 , includes a plurality of spring biased clips  732  which are configured to couple with a retaining feature, such as a groove  734 , on jet body  704  ( 404 ). In the embodiment shown in  FIGS. 28-29 , jet back  702  includes four spring biased clips  732 . In some examples, spring biased clips  732  may include a resiliently flexible support  736  and a sloped lip  738  which is configured to engage with groove  734 . 
     In some examples, the attachment mechanism may be configured to couple jet back  702  to jet body  704  while allowing jet back  702  to rotate relative to jet body  704 . In other words, in some examples, jet back  702  may able to rotate about longitudinal axis  714  when coupled to jet body  704  while maintaining a water- and air-tight seal; this may allow a worker to prevent adjacent jet assemblies from interfering with each other. 
     Jet body  704  includes two recesses  740  disposed on upstream portion  724  and configured to contain one or more O-rings  742 , such as those shown in  FIG. 28 . Recesses  740  may be configured such that the outside edge of the O-ring is flush with or extends slightly beyond the surface of the upstream portion of the jet body as shown in  FIG. 28 . As best seen in  FIG. 29 , jet back  702  also includes a spacing mechanism configured to ensure sufficient space between a proximate end  744  of upstream portion  724  of jet body  704  ( 404 ) and an inner wall  746  of jet back  702 . In the example shown in  FIG. 29 , jet back  702  includes four spacers  748  disposed on inner wall  746  and formed as an integral part of jet back  702 . 
     The embodiment of jet back  702  shown in  FIGS. 28-29  includes a nozzle  708  which is substantially identical to nozzle  408  and which includes a structure formed as an integral part of jet back  702 . Nozzle  708  may include any suitable structure formed as part of jet back  402  and configured to change the direction and/or speed of the stream of water. As can best be seen in  FIG. 29 , inner wall  746  of jet back  702  includes a conical portion  750  narrowing to a first aperture  752 . Water ingress port  712  extends from a substantially cylindrical portion to a conical cavity  754  which tapers to first aperture  752 . In some examples, conical cavity  754  may be similar in shape to conical portion  348  of nozzle  308 . 
     Upstream portion  724  of jet body  704  includes a conical chamber  756 . Conical chamber  756  may be shaped to receive nozzle  708  of jet back  702 . In some examples, the shape of conical chamber  756  of jet body  704  ( 404 ) may be substantially complementary to the shape of conical portion  750 . In some examples, the shape of conical chamber  756  may be significantly wider than conical portion  750  and may have a height that is equal to or greater than the height of conical portion  750 . A difference in size and shape between conical chamber  756  and conical portion  750  may be used to ensure that there is a space between conical portion  750  and conical chamber  756 . In the embodiment shown in  FIGS. 28-29 , spacers  748  are also included to ensure that there is space between conical portion  750  and conical chamber  756 . 
     In use, water passes through a water ingress port  710 , through conical cavity  754  and first aperture  752 , and into the space between conical portion  750  and conical chamber  756 . Air ingress port  712  leads to the space between conical portion  750  and conical chamber  756 . The streams of air and water may merge in the space between conical portion  750  and conical chamber  756  and/or in conical chamber  756  before passing through second aperture  758 . Second aperture  758  connects conical chamber  756  with a receiving chamber. 
     In other words, water ingress port  710  extends from a first substantially cylindrical portion to a second substantially cylindrical portion at a right angle to the first cylindrical portion. From the second substantially cylindrical portion, water ingress port  710  proceeds to conical cavity  754  which leads to first aperture  752 . When jet back  702  and jet body  704  ( 404 ) are coupled together, first aperture  752  leads to a conical chamber  756 . Air ingress port  712  also leads to conical chamber  756 . The streams of air and water may merge in conical chamber  756  before passing through second aperture  758 . 
     As discussed above, jet body  704  is substantially identical to jet body  404  and the jet insert for jet assembly  700  is substantially identical to the jet insert for jet assembly  400 . Accordingly, only an abbreviated description of jet body  704 , the jet insert, and how the jet body and jet insert interface will be provided. The receiving chamber may be primarily disposed within downstream portion  726  and includes a substantially cylindrical cavity. Similar to the first style of jet body  304 , jet body  704  (jet body  404 ) further includes two substantially rectangular protrusions disposed on an inner wall of the receiving chamber which may be used as a spacing mechanism. Two hooks may be disposed inside of the receiving chamber to facilitate coupling with a jet insert. The hooks may include an approximately U-shaped structure wherein one side is shorter than the other. In some examples, jet body  704  (jet body  404 ) may include any suitable number of hooks, which may include any suitable structure for engaging the jet insert. 
     As discussed with respect to jet assembly  300  and  400 , jet assembly  700  may include one or more versions of the jet insert and jet body  704  ( 404 ). For example, one or more different sizes and/or styles of jet body  704  ( 404 ) may be configured to couple with a single style of jet back  702  and each of the one or more versions of jet body  704  ( 404 ) may be configured to couple with one or more versions of the jet insert. In other words, a variety of styles of jet body may be installed in multiple places on a hot tub  100  and different styles of jet insert may be coupled to each jet body depending on the location within the hot tub and the features of the jet body. In some examples, jet assembly  700  may include only one version of jet body  704  ( 404 ) and/or only one version of the jet insert. 
     Only one size of jet body  704  ( 404 ) is shown in the drawings. In the style of jet body  704  ( 404 ) depicted in  FIG. 28 , the maximum diameter of downstream portion  726  is approximately 2.0 inches. Additionally, downstream portion  726  includes a flange  728  and a channel disposed on flange  728 . 
     As discussed with respect to jet body  404 , downstream portion  726  of other sizes of jet body  704  ( 404 ) may include any suitable maximum diameter. For example, the maximum diameter of downstream portion  726  may be between approximately 1.0 inches and approximately 5.0 inches. In some examples, four sizes of jet body may be used having maximum diameters of approximately 2.0 inches, approximately 3.0 inches, approximately 4.0 inches, and approximately 5.0 inches respectively. With the exception of the diameter of downstream portion  726  and certain features of the receiving chamber, each size of jet body  704  may be substantially identical. Features of the receiving chamber, such as the hooks, may differ between versions of jet body  704  to best couple and position a suitable version of the jet insert within each jet body. Each size of jet body  704  ( 404 ) may be used and installed in hot tub shell  104  in substantially the same way. Jet body  704  may be used and installed in hot tub shell  104  in substantially the same way as jet body  404 . Further, each style of jet body couples with jet back  702  in a substantially identical way. 
     During installation, jet assembly  700  may be assembled in multiple steps and/or at multiple stations. A first step may include coupling the air and water ingress ports of jet back  702  with tubing  120 . Jet back  702  may couple with tubing  120  in a way that is substantially similar to the way that jet back  402  couples with tubing  120 ; the primary difference may be the orientation of the tubing relative to the longitudinal axis of the jet back. Coupling the air and water ingress ports of jet back  702  with tubing  120  may include any suitable process and/or structure. For example, tubing  120  may be slid over the ends of the air and water ingress ports of jet back  702  and a clamp (described in more detail below) may be used to prevent the tubing from sliding off. In some examples, a lubricant (e.g. soapy water) may be used to facilitate sliding the tubing over the ingress ports. In some examples, tubing  120  may include dual extrusion tubing. In some examples, tubing  120  may include separate air and water tubes which may be installed one at a time on the air and water ingress ports respectively. 
     Another step in installing jet assembly  700  may include installing jet body  704  ( 404 ) and the jet insert in or on hot tub shell  104 . For example, jet body  704  ( 404 ) may be inserted into a hole formed in hot tub shell  104 . Jet body  704  ( 404 ) may be inserted from the interior of hot tub shell  104  and may be secured to hot tub shell  104  by any suitable mechanism configured to be water tight and secure. For example, jet body  704  ( 404 ) may attach to hot tub shell  104  via threaded engagement, glue, press-fitting, and/or any other suitable attachment mechanism. In some examples, attaching jet body  704  ( 404 ) may include threading the jet body into the hot tub shell and/or the use of a compressive gasket. 
     The jet insert may be coupled to jet body  704  ( 404 ) from the interior of hot tub shell  104  after jet body  704  ( 404 ) has been installed in hot tub shell  104 . As discussed above and with respect to jet assembly  400 , jet body  704  ( 404 ) is configured to securely couple with and position the jet insert. In some examples, jet body  704  ( 404 ) and/or the jet insert may be installed from the exterior of hot tub shell  104 . In some examples, jet body  704  ( 404 ) and the jet insert may couple together through a hole in the hot tub shell, thereby attaching both parts to the hot tub shell. 
     Completing the installation of jet assembly  700  may include coupling jet back  702  (which is attached to tubing  120 ) to jet body  704  ( 404 ) (which is attached to hot tub shell  104 ). Jet back  702  may be coupled with jet body  704  ( 404 ) by a “press-and-click” method (described above). For example, jet back  702  and jet body  704  ( 404 ) may be aligned and then compressed together to overcome the resistive force of spring biased clips  732 . In the embodiment shown in  FIGS. 28-29 , spring biased clips  732  are configured to flex outward, away from a default position (e.g., away from longitudinal axis  714 ), when sloped lip  738  slides over proximate end  744  of jet body  704  ( 404 ) and along an external portion of upstream portion  724 . Spring biased clips  732  are further configured to snap back into the default position (e.g., back towards longitudinal axis  714 ) when sloped lip  738  encounters groove  734  of jet body  704  ( 404 ). Sloped lip  738  prevents spring biased clips  732 , and thus jet back  702 , from sliding towards proximate end  744  and off of jet body  704  ( 404 ). Thus, jet back  702  and jet body  704  are coupled together. 
     In some examples, jet back  702  and jet body  704  ( 404 ) may be configured to be able to be unlocked and/or uncoupled. Uncoupling jet back  702  from jet body  704  ( 404 ) may be accomplished by moving spring biased clips  732  away from jet body  704  ( 404 ) (e.g., away from longitudinal axis  714 ) and sliding the jet back off of the jet body. In some examples, a worker may accomplish this using a finger to move the spring biased clips and/or using a tool. Releasably coupling the jet back and the jet body together may be advantageous as it may, among other advantages, allow a worker to uncouple a jet back that was coupled to the wrong jet body by mistake. 
     Each of the components of jet assembly  700  (e.g., jet back  702 , jet body  704  ( 404 ), and a compatible jet insert) may be constructed out of any suitable material. For example, the components of jet assembly  700  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). The components of jet assembly  700  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     Third Angled Back Embodiment 
       FIG. 30  depicts a sixth embodiment  800  of jet assembly  200 , which also includes an angled back jet back. The sixth embodiment of jet assembly  200  is generally indicated at  800  and includes an angled jet back  802 , a jet body  804 , and a jet insert  806 . Additionally, or alternatively, jet assembly  800  may be referred to as a jet, a jet assembly, an angled jet, an angled jet assembly, an angled back jet, and/or an angled back jet assembly. Additionally, or alternatively, jet back  802  may be referred to as an angled back jet back or an angled jet back. Additionally, or alternatively, the jet insert may be referred to as a jet face. Jet back  802  is an example of jet back  202  described above, jet body  804  is an example of jet back  204  described above, and jet insert  806  is an example of jet insert  206  described above. 
     Many of the features of sixth embodiment  800  of jet assembly  200  are the same as third embodiment  500 . The primary difference between angled jet assembly  800  and straight back jet assembly  500 , is the shape of angled jet back  802  compared with jet back  502 . Whereas jet back  502  includes air and water ingress ports which are parallel to a longitudinal axis of the jet back, angled jet back  802  includes air and water ingress ports which are not parallel to a longitudinal axis of the jet back. Accordingly, jet body  804  and jet insert  806  of angled jet  800  are substantially similar to jet body  504  and jet insert  506  of jet  500 . Accordingly, similar components and/or features may be labeled with similar reference numbers and only an abbreviated discussion of such features will be provided here. The differences between the embodiments are described in detail below. 
       FIG. 30  is a fully assembled isometric view of angled back jet  800  and components thereof. As seen in  FIG. 30 , angled back jet assembly  800  includes angled jet back  802 , jet body  804 , and jet insert  806 . Jet body  804  and jet insert  806  are substantially similar to jet body  504  and jet insert  506  respectively. Jet back  802  is substantially similar to jet back  502 ; the primary difference between jet back  502  and angled jet back  802  is the configuration of the air and water ingress ports. Specifically, the air and water ingress ports extend at an angle with respect to the longitudinal axis of the jet back. The air and water ingress ports of jet back  802  are substantially similar to the air and water ingress ports of jet back  602  and jet back  702 . In contrast with angled jets  600  and  700 , water ingress port  810  does not include a lip (such as lip  620  or  720 ). Instead, water ingress port  810  has a substantially smooth external surface. 
     Jet back  802  includes two ingress ports: a water ingress port  810  and an air ingress port  812 . Water ingress port  810  is larger in diameter than air ingress port  812  and at least a portion of water ingress port  810  is parallel to air ingress port  812 . In the embodiment shown in  FIG. 30 , water ingress port  810  includes a base portion  816  and an extended portion  818 . Base portion  816  is substantially centered on longitudinal axis  814  of the jet back and is substantially parallel with longitudinal axis  814 . Extended portion  818  may be oriented at any suitable angle relative to base portion  816 . In the embodiment shown in  FIG. 30 , extended portion  818  is oriented at an approximately 90-degree angle with respect to base portion  816 . Additionally, or alternatively, water ingress port  810  may be referred to as a water barb, an angled water ingress port, or an angled water barb. 
     Air ingress port  812  is substantially parallel with extended portion  818  and may be offset from the center of jet back  802 . Air ingress port  812  may form substantially the same angle with longitudinal axis  814  as extended portion  818 . For example, air ingress port  812  may form an approximately 90-degree angle with longitudinal axis  814 . In some examples, air ingress port  812  may extend from the side of jet back  802 . Additionally, or alternatively, air ingress port  812  may be referred to as an air barb, an angled air barb, or an angled air ingress port. An external portion of air ingress port  812  may be smooth as can be seen in  FIG. 30 . 
     In the embodiment shown in  FIG. 30 , jet back  802  is configured to couple with dual extrusion tubing having two parallel passages joined at a periphery (examples of dual extrusion tubing are discussed in more detail below). In some examples, jet back  802  may be configured to couple with any other suitable kind of tubing. Similar to jet back  502 , jet back  802  further includes a central portion  822  configured to create a water tight seal with jet body  804 . Central portion  822  is in direct fluid communication with water ingress port  810  and air ingress port  812  and may include any suitable shape depending on the application and on the characteristics of the jet body. In this embodiment, central portion  822  is substantially cylindrical as can be seen in  FIG. 30 . 
     As in previous embodiments, jet body  804  includes an upstream portion  824  and a downstream portion  826  wherein the upstream portion is configured to be at least partially disposed within central portion  822  of jet back  802 . Jet back  802  includes an attachment mechanism extending from a first end  830  of central portion  822  and configured to couple the jet back to jet body  804  in a secure manner. The attachment mechanism, like the attachment mechanism for jets  600  and  700 , includes a plurality of spring biased clips  832  which are configured to couple with a retaining feature, such as a groove  834 , on jet body  804 . In the embodiment shown in  FIG. 30 , jet back  802  includes four spring biased clips  832 . In some examples, spring biased clips  832  may include a resiliently flexible support  838  and a sloped lip  840  which is configured to engage with groove  834 . 
     In some examples, the attachment mechanism may be configured to couple jet back  802  to jet body  804  while allowing jet back  802  to rotate relative to jet body  804 . In other words, in some examples, jet back  802  may able to rotate about longitudinal axis  814  when coupled to jet body  804  while maintaining a water- and air-tight seal; this may allow a worker to prevent adjacent jet assemblies from interfering with each other. 
     Similar to previous embodiments, jet body  804  may include one or more recesses disposed on upstream portion  824  and configured to contain one or more O-rings. In some examples, jet back  802  may include a spacing mechanism configured to ensure sufficient space between a proximate end of upstream portion  824  of jet body  804  and an inner wall of jet back  802 . In some embodiments, jet back  802  may include a nozzle which is substantially identical to nozzle  508  and which includes a structure formed as an integral part of jet back  802 . For example, a compatible nozzle may include any suitable structure formed as part of jet back  802  and configured to change the direction and/or speed of the stream of water. 
     In some examples, an inner wall of jet back  802  may include a conical portion narrowing to a first aperture and water ingress port  812  may extend from a substantially cylindrical portion to a conical cavity which tapers to the first aperture. In some examples, the conical cavity may be similar in shape to conical portion  348  of nozzle  308 . In some examples, upstream portion  824  of jet body  804  may include a conical chamber shaped to receive a nozzle of jet back  802 . In some embodiments, spacers may be included to ensure that there is space between the conical portion and the conical chamber. In use, the streams of air and water may merge in the space between the conical portion and the conical chamber and/or in the conical chamber before passing through to a receiving chamber. 
     In other words, water ingress port  810  extends from a first substantially cylindrical portion to a second substantially cylindrical portion at a right angle to the first cylindrical portion. From the second substantially cylindrical portion, water ingress port  810  may proceed to a conical cavity which leads to a first aperture. When jet back  802  and jet body  804  are coupled together, the first aperture may lead to a conical chamber. Air ingress port  812  may also lead to a conical chamber. The streams of air and water may merge in the conical chamber before passing through to a receiving chamber. 
     As discussed above, jet body  804  is substantially similar to jet body  504  and jet insert  806  is substantially identical to jet insert  506 . Accordingly, only an abbreviated description of jet body  804  and jet insert  806 , and how the jet body and jet insert interface will be provided. In some embodiments, jet body  804  may include a receiving chamber disposed within downstream portion  826 . The receiving chamber may include any suitable structures configured to couple with and suitably position jet insert  806 . In some examples, the receiving chamber may include protrusions on an inner wall which may be used as a spacing mechanism and/or a plurality of hooks configured to couple with teeth on jet insert  806 . 
     As discussed with respect to previous embodiments of jet assembly  200 , jet assembly  800  may include one or more versions of jet insert  806  and jet body  804 . For example, one or more different sizes and/or styles of jet body  804  may be configured to couple with a single style of jet back  802  and each of the one or more versions of jet body  804  may be configured to couple with one or more versions of jet insert  806 . In other words, a variety of styles of jet body may be installed in multiple places on a hot tub  100  and different styles of jet insert may be coupled to each jet body depending on the location within the hot tub and the features of the jet body. In some examples, jet assembly  800  may include only one version of jet body  804  and/or only one version of jet insert  806 . 
     Only one size of jet body  804  is shown in the drawings. In the style of jet body  804  depicted in  FIG. 30 , the maximum diameter of downstream portion  826  is approximately 2.0 inches. Additionally, downstream portion  826  includes a flange  828 . 
     As discussed with respect to jet body  504 , downstream portion  826  of other sizes of jet body  804  may include any suitable maximum diameter. For example, the maximum diameter of downstream portion  826  may be between approximately 1.0 inches and approximately 5.0 inches. In some examples, four sizes of jet body may be used having maximum diameters of approximately 2.0 inches, approximately 3.0 inches, approximately 4.0 inches, and approximately 5.0 inches respectively. With the exception of the diameter of downstream portion  826 , each size of jet body  804  may be substantially identical. Some of the features of downstream portion  826  may differ between versions of jet body  804  to best couple and position a suitable version of jet insert  806  within each jet body. Each size of jet body  804  may be used and installed in hot tub body  104  in substantially the same way. Jet body  804  may be used and installed in hot tub shell  104  in substantially the same way as jet body  504 . Further, each style of jet body couples with jet back  802  in a substantially identical way. 
     During installation, jet assembly  800  may be assembled in multiple steps and/or at multiple stations. A first step may include coupling the air and water ingress ports of jet back  802  with tubing  120 . Jet back  802  may couple with tubing  120  in a way that is substantially similar to the way that jet back  502  couples with tubing  120 ; the primary difference may be the orientation of the tubing relative to the longitudinal axis of the jet back. Coupling the air and water ingress ports of jet back  802  with tubing  120  may include any suitable process and/or structure. For example, tubing  120  may be slid over the ends of the air and water ingress ports of jet back  802  and a clamp (described in more detail below) may be used to prevent the tubing from sliding off. In some examples, a lubricant (e.g. soapy water) may be used to facilitate sliding the tubing over the ingress ports. In some examples, tubing  120  may include dual extrusion tubing. In some examples, tubing  120  may include separate air and water tubes which may be installed one at a time on the air and water ingress ports respectively. 
     Another step in installing jet assembly  800  may include installing jet body  804  and jet insert  806  on hot tub  104 . For example, jet body  804  may be inserted into a hole formed in the shell of hot tub  104 . Jet body  804  may be inserted from the interior of hot tub shell  104  and may be secured to hot tub shell  104  by any suitable mechanism configured to be water tight and secure. For example, jet body  804  may attach to hot tub shell  104  via threaded engagement, glue, press-fitting, and/or any other suitable attachment mechanism. In some examples, attaching jet body  804  may include threading the jet body into the hot tub body and/or the use of a compressive gasket. 
     Jet insert  806  may be coupled to jet body  804  from the interior of hot tub shell  104  after jet body  804  has been installed in hot tub shell  104 . As discussed above and with respect to jet assembly  500 , jet body  804  is configured to securely couple with and position jet insert  806 . In some examples, jet body  804  and/or jet insert  806  may be installed from the exterior of hot tub shell  104 . In some examples, jet body  804  and jet insert  806  may couple together through a hole in the hot tub shell, thereby attaching both parts to the hot tub shell. 
     A further step in the installation of jet assembly  800  may include coupling jet back  802  (which is attached to tubing  120 ) to jet body  804  (which is attached to hot tub shell  104 ). Jet back  802  may be coupled with jet body  804  by a “press-and-click” method (described above). For example, jet back  802  and jet body  804  may be aligned and then compressed together to overcome the resistive force of spring biased clips  832 . In the embodiment shown in  FIG. 30 , spring biased clips  832  are configured to flex outward, away from a default position (e.g., away from longitudinal axis  814 ), when sloped lip  840  slides over proximate end  846  of jet body  804  and along an external portion of upstream portion  824 . Spring biased clips  832  are further configured to snap back into the default position (e.g., back towards longitudinal axis  814 ) when sloped lip  840  encounters groove  834  of jet body  804 . Sloped lip  840  prevents spring biased clips  832 , and thus jet back  802 , from sliding towards proximate end  846  and off of jet body  804 . Thus, jet back  802  and jet body  804  are coupled together. 
     In some examples, jet back  802  and jet body  804  may be configured to be able to be unlocked and/or uncoupled. Uncoupling jet back  802  from jet body  804  may be accomplished by moving spring biased clips  832  away from jet body  804  (e.g., away from longitudinal axis  814 ) and sliding the jet back off of the jet body. In some examples, a worker may accomplish this using a finger to move the spring biased clips and/or using a tool. Releasably coupling the jet back and the jet body together may be advantageous as it may, among other advantages, allow a worker to uncouple a jet back that was coupled to the wrong jet body by mistake. 
     Each of the components of jet assembly  800  (e.g., jet back  802 , jet body  804 , and jet insert  806 ) may be constructed out of any suitable material. For example, the components of jet assembly  800  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). The components of jet assembly  800  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     System Using Both Straight and Angled Jets 
     As described above, a single plumbing system may include both straight back jet assemblies and angled back jet assemblies. A combination of styles of jet backs may be advantageous in situations where a hot tub includes areas having little space between hot tub shell  104  and hot tub frame  102 . 
     As has been indicated, jets  300  and  600 , jets  400  and  700 , and jets  500  and  800 , are each substantially similar to the other except for the orientation of the air and water ingress ports. For example, jets  300  and  600  are substantially the same except that jet  600  has air and water ingress ports oriented at an angle relative to longitudinal axis  614  (which corresponds to longitudinal axis  314 ) whereas jet  300  has air and water ingress ports that are parallel to longitudinal axis  314 . Thus, a jet body  304 / 604  can be coupled with either a straight jet back  302  or an angled jet back  602 . This may be useful in a plumbing system, as the same kind of jet body can be installed in all jet locations on a hot tub, and a worker can couple either a straight back jet back ( 302 ) or an angled back jet back ( 602 ) to the jet body as needed depending on the location within the hot tub. Accordingly, jets  300  and  600  may form a jet system. 
     In embodiments which include multiple sizes of jet body  304 / 604 , each size of jet body may be configured to be able to couple with either a straight back jet back or an angled back jet back. In other words, different sizes of jet body may be installed in different locations on hot tub shell  104  depending on the application and/or the design of the hot tub, and either a straight back jet back or an angled back jet back may be coupled to each jet body depending only on the amount of space available adjacent to the jet body. Further, the style and/or size of the jet insert which is coupled to each jet body depends on the size of the jet body and/or the design of the hot tub but may be independent of the style of jet back used at that location. 
     B. Illustrative Manifold Assembly 
     This section describes illustrative embodiments of a set of manifold assembly components; see  FIGS. 31-53 . 
       FIG. 31  is a block diagram of a plumbing system showing how manifolds may be integrated into the system. A hot tub air and water supply manifold assembly, generally indicated at  910 , may be formed using one or more manifold assembly components. Illustrative hot tub air and water supply manifold assembly  910  may also be referred to as a manifold assembly. The set of manifold assembly components may include an air and water supply manifold  920 , a male manifold adapter  930 , a female manifold adapter  940 , and a manifold end cap  950 . 
     Additionally, or alternatively, air and water supply manifold  920  may be referred to as a hot tub manifold, a hot tub air and water manifold, a supply manifold, and/or a manifold. Air and water supply manifold  920  is an example of manifold  118 , described above. Additionally, or alternatively, male manifold adapter  930  may be referred to as a male adapter. Male adapter  930  is an example of adapter  110 , described above. Additionally, or alternatively, female manifold adapter  940  may be referred to as a female adapter. Female adapter  940  is an example of adapter  128 , described above. Additionally, or alternatively, manifold end cap  950  may be referred to as an end cap. End cap  950  is an example of end cap  130 , described above. Accordingly, similar components may be labeled with similar reference numbers. 
     Manifold System Overview 
     The set of manifold assembly components includes each of the components used in forming a manifold assembly. The set of manifold assembly components includes manifold  920 , male adapter  930 , female adapter  940 , and end cap  950 . Manifold assembly  910  is composed of any suitable number of each of the components in the set of manifold assembly components and may include any suitable structures configured to separately convey air and water from respective air and water sources to a plurality of lengths of tubing  120 . For example, manifold assembly  910  may include male adapter  930 , any suitable number of manifolds  920 , and female adapter  940  or end cap  950 . In some examples, hot tub  100  may include any suitable number of manifold assemblies  910 . Each manifold assembly  910  may include any suitable number of manifolds  920 . In some examples, manifold assembly  910  may not include female adapter  940  and/or end cap  950 . 
       FIG. 31  is a block diagram which includes two illustrative manifold assemblies  910  and depicts an example of how manifold assembly  910  may interact with other plumbing components. As seen in  FIG. 31 , male adapter  930  receives air and water from air tubing  116  and pipe  112  respectively. Male adapter  930  is in fluid communication with manifold  920 . Each manifold  920  may be in fluid communication with tubing  120  and with female adapter  940 , end cap  950 , and/or one or two other manifolds  920 . Sometimes manifold assembly  910  may include female manifold  940  and sometimes manifold assembly  910  may include end cap  950 . This is shown in  FIG. 31 : one of the illustrative manifold assemblies  910  in  FIG. 31  includes female manifold  940  and the other illustrative manifold assembly  910  includes end cap  950 . In  FIG. 31 , both illustrative manifold assemblies  910  include three manifolds  920 , however, manifold assembly  910  may include more or less than three manifolds  920 . Each of the components of manifold assembly  910  and how the components may couple together is described in more detail in the following sections. 
     Manifold  920  may include any suitable structures configured to separately receive air and water from a second component, to pass a first portion of the air and water as separate streams to a third component, and to allow a second portion of the air and water to pass as separate streams to tubing  120 . The second component may include male adapter  930  or another manifold  920 . The third component may include female adapter  940 , end cap  950 , or another manifold  920 . Manifold  920  may receive air and water from the second component as separate air and water supply streams. 
     Manifold  920  is configured to couple with the second and third components and with tubing  120 . For example, an upstream end of manifold  920  may be configured to releasably couple with the second component and a downstream end of manifold  920  may be configured to releasably couple with the third component. Manifold  920  may include any suitable structure configured to form a water and/or air tight connection with the second and third components such that manifold  920  is in fluid communication with the second and third components and such that the streams of air and water remain separate. For example, manifold  920  may include a water conduit which is in fluid communication with water conduits of the second and third components and an air conduit which is in fluid communication with air conduits of the second and third components. 
     Manifold  920  may further include any suitable structure configured to form a water and/or air tight connection with tubing  120  such that manifold  920  passes the second portion of the air and water to tubing  120  as separate streams. For example, manifold  920  may include air and water egress ports which may be in fluid communication with tubing  120 . In some examples, coupling manifold  920  to tubing  120  may include using a clamp. 
     Male adapter  930  may include any suitable structures configured to separately receive air from air tubing  116  and water from pipe  112 , and to pass the air and water as separate streams to a manifold  920 . Male adapter  930  is configured to couple with at least manifold  920 , air tubing  116 , and pipe  112 . For example, an upstream end of male adapter  930  may be configured to couple with air tubing  116  and with pipe  112 , and a downstream end may be configured to releasably couple with manifold  920 . Male adapter  930  may include any suitable structure configured to form a water and/or air tight connection with air tubing  116  and pipe  112  such that male adapter  930  is in fluid communication with air tubing  116  and pipe  112  and such that the streams of air and water remain separate. Male adapter  930  may further include any suitable structure configured to form a water and/or air tight connection with manifold  920  such that male adapter  930  is in fluid communication with manifold  920  and such that the streams of air and water remain separate. For example, male adapter  930  may include a water conduit which is in fluid communication with pipe  112  and with a water conduit of manifold  920  and an air conduit which is in fluid communication with air tubing  116  and with an air conduit of manifold  920 . 
     Female adapter  940  may include any suitable structures configured to separately receive air and water from manifold  920 , and to pass the air and water as separate streams to air tubing  116  and pipe  112 . Female adapter  940  is configured to couple with at least manifold  920 , air tubing  116 , and pipe  112 . For example, an upstream end of female adapter  940  may be configured to releasably couple with manifold  920 , and a downstream end of female adapter  940  may be configured to couple with air tubing  116  and with pipe  112 . Female adapter  940  may include any suitable structure configured to form a water and/or air tight connection with manifold  920  such that female adapter  940  is in fluid communication with manifold  920  and such that the streams of air and water remain separate. Female adapter  940  may further include any suitable structure configured to form a water and/or air tight connection with air tubing  116  and pipe  112  such that female adapter  940  is in fluid communication with air tubing  116  and pipe  112  and such that the streams of air and water remain separate. For example, female adapter  940  may include a water conduit which is in fluid communication with a water conduit of manifold  920  and with pipe  112  and an air conduit which is in fluid communication with an air conduit of manifold  920  and with air tubing  116 . 
     End cap  950  may include any suitable structures configured to end the streams of air and water while keeping the streams of air and water separate. End cap  950  is configured to couple with at least manifold  920 . For example, an upstream end of end cap  950  may be configured to releasably couple with manifold  920 , and a downstream end of end cap  950  may be sealed so as to prevent the flow of air and/or water out of the plumbing system. End cap  950  may include any suitable structure configured to form a water and/or air tight connection with manifold  920  such that the flow of air and/or water ends and such that the streams of air and water remain separate. For example, end cap  950  may include a water cap which couples with a water conduit of manifold  920  and an air cap which couples with an air conduit of manifold  920 . 
     In a plumbing system according to the present teachings, one or more manifolds  920  may be used in combination with one or more other components. For example, male adapter  930  may provide air and water as separate streams to a first manifold  920 , the first manifold may be in fluid communication with one or more other manifolds  920 , and end cap  950  may be coupled with a last manifold  920 . In some examples, female adapter  940  may be coupled with the last manifold in place of an end cap. In some examples, female adapter  940  may be couple with another length of pipe  112  which leads to a second male adapter  930  which is coupled to another group of manifolds. Together, male adapter  930 , one or more manifolds  920 , and female adapter  940  or end cap  950  form manifold assembly  910 . 
     This section includes a description of two possible embodiments of set of manifold assembly components  900 . A person of ordinary skill in the art will recognize that other embodiments or variations of each component are possible. 
     First Embodiment of a Manifold 
       FIGS. 32-36  depict various views of a first embodiment  1000  of hot tub air and water multi-port supply manifold  920  which is suitable for use in a first embodiment  912  of manifold assembly  910 . Hot tub air and water supply manifold  1000  is an example of manifold  920  described briefly above and forms part of a first embodiment of the set of manifold assembly components. Accordingly, similar components may be labeled with similar reference numbers. 
       FIG. 32  is an oblique isometric view of manifold  1000 ;  FIG. 32  shows two O-rings.  FIG. 33  is a top plan view of manifold  1000  without the O-rings.  FIG. 34  is a bottom plan view of manifold  1000 .  FIG. 35  is a front elevation view of manifold  1000  and  FIG. 36  is a side elevation view of manifold  1000 .  FIG. 37  is an oblique isometric view of two manifolds  1000  coupled together. 
     Manifold  1000  includes a water conduit  1002  defining a first longitudinal axis  1004 . Water conduit  1002  may include any suitable structure configured to receive water from the second component and to deliver at least a first portion of the water to the third component. In some examples, water conduit  1002  may receive water from the second component as a water supply stream. For example, water conduit  1002  may be a substantially cylindrical tube as in  FIGS. 32-36 . Manifold  1000  further includes at least one air conduit  1006  defining a second longitudinal axis  1008 . Air conduit  1006  may include any suitable structure configured to receive air from the second component and to deliver at least a first portion of the air to the third component. In some examples, air conduit  1006  may receive air from the second component as an air supply stream. For example, air conduit  1006  may include a substantially cylindrical tube as in  FIGS. 32-36 . 
     In this embodiment, second longitudinal axis  1008  is substantially parallel to first longitudinal axis  1004  and air conduit  1006  includes a periphery  1010  joined to a periphery  1012  of water conduit  1002  via support structure  1014 . Support structure  1014  may include any suitable structure for rigidly connecting air conduit  1006  to water conduit  1002 . For example, support structure  1014  may include a rigid strut as best seen in  FIGS. 32-35 . In some examples, second longitudinal axis  1008  may have any suitable orientation with respect to first longitudinal axis  1004  and air conduit  1006  may be joined with water conduit  1002  in any suitable manner. 
     Manifold  1000  may include any suitable number of water conduits  1002  and air conduits  1006 . For example, in the embodiment shown in  FIGS. 32-36 , manifold  1000  includes two air conduits  1006  rigidly connected to one water conduit  1002 . In embodiments having two or more air conduits  1006 , the two or more second longitudinal axes  1008  may have any suitable disposition and/or orientation in relation to first longitudinal axis  1004 . In the embodiment shown in  FIGS. 32-36 , two second longitudinal axes  1008  are disposed on either side of, and lie in a plane with, first longitudinal axis  1004 . That is, the two air conduits are disposed on opposite sides of the water conduit. In other words, in the embodiment shown in  FIGS. 32-36 , a first air conduit is joined to a first portion of the periphery of the water conduit, a second air conduit is joined to a second portion of the periphery of the water conduit, and the first and second portions of the periphery of the water conduit are separated from each other by approximately 180 degrees. 
     Manifold  1000  further includes a water egress port  1016  in fluid communication with water conduit  1002  and an air egress port  1018  in fluid communication with air conduit  1006 . Water egress port  1016  and air egress port  1018  are disposed substantially parallel and adjacent to each other and are configured to channel streams of water and air, respectively, to a length of tubing (such as tubing  120 ). Additionally, or alternatively, water egress port  1016  may be referred to as a water barb and/or air egress port  1018  may be referred to as an air barb. In some examples, water egress port  1016  may be larger than air egress port  1018 . 
     Water egress port  1016  and air egress port  1018  may include any suitable structures configured to form a water tight seal with tubing  120 . For example, water egress port  1016  may include a lip or ridge  1020  as can best be seen in  FIGS. 35 and 36 . Lip  1020  may include any suitable structure configured to ensure a water tight seal between water egress port  1016  and a length of tubing (such as tubing  120 ). For example, lip  1020  may include a sloped ridge as can best be seen in  FIGS. 35 and 36 . In some examples, air egress port  1018  may include a lip or other feature to ensure a seal. In some examples, an external portion of air egress port  1018  may be smooth as can best be seen in  FIGS. 35 and 36 . 
     Together water egress port  1016  and air egress port  1018  form a set of egress ports  1022 . Manifold  1000  may include one or more sets of egress ports  1022 . For example, the embodiment in  FIGS. 32-36  includes two sets of egress ports  1022 . In some examples, manifold  1000  may include a number of sets of egress ports  1022  that is substantially the same as the number of air conduits  1006  and each air egress port  1018  may be in fluid communication with a different air conduit  1006 . In some examples, manifold  1000  may include a number of sets of egress ports  1022  that is substantially the same as or greater than the number of air conduits  1006  and two or more air egress ports  1018  may be in communication with the same air conduit. In some examples, manifold  1000  includes only one water conduit  1002  and all of the one or more water egress ports  1016  may be in fluid communication with the same water conduit. 
     In the embodiment of manifold  1000  shown in  FIGS. 32-36 , manifold  1000  includes one water conduit  1002 , two air conduits  1006  separated by approximately 180 degrees, and two sets of egress ports  1022 . In this embodiment, one air egress port  1018  is in communication with each air conduit  1006 . In this embodiment, both sets of egress ports  1022  are disposed on the top of manifold  1000 , and each water egress port  1016  and each air egress port  1018  are oriented substantially perpendicular to water conduit  1002  and air conduit  1006  respectively. In some embodiments, one or more of the sets of egress ports  1022  may be disposed on the top of manifold  1000  and/or one or more of the sets of egress ports  1022  may be disposed on the bottom of manifold  1000 . In some examples, water egress port  1016  and air egress port  1018  may have any suitable orientation relative to water conduit  1002  and air conduit  1006 . 
     In the embodiment shown in  FIGS. 32-36 , each water egress port  1016  is disposed on a central portion of manifold  1000  approximately equidistant from downstream end  1026  and upstream end  1024 , and each air egress port  1018  is disposed on a central portion of manifold  1000  approximately equidistant from downstream end  1030  and upstream end  1028 . In some examples, each water egress port  1016  and each air egress port  1018  may be disposed on any suitable portion of water conduit  1002  and air conduit  1006  respectively and may be any suitable distance from a respective downstream and/or upstream end. 
     In the embodiment shown in  FIGS. 32-36 , each set of egress ports  1022  is configured to couple with dual extrusion tubing having two parallel passages joined at a periphery (examples of dual extrusion tubing are discussed below). In embodiments where each set of egress ports  1022  is configured to couple with dual extrusion tubing, water egress port  1016  may be configured to couple with a first passage of the dual extrusion tubing and air egress port  1018  may be configured to couple with a second passage of the dual extrusion tubing. In this way, the streams of air and water are kept separate while being conveyed by the same length of tubing. In some examples, each set of egress ports  1022  may be configured to couple with any suitable kind of tubing. For example, each set of egress ports  1022  may be configured to couple with two separate lengths of tubing, one which carries air and one which carries water. In some examples, configuring set of egress ports  1022  to couple with different kinds of tubing may include changing the spacing between the air and water egress ports and/or the dimensions of the air and water egress ports. 
     Manifold  1000  may be further configured to couple with one or more other components. For example, water conduit  1002  may include an upstream end  1024  and a downstream end  1026  wherein upstream end  1024  is configured to couple with the downstream end of a water conduit of the second component and downstream end  1026  is configured to couple with the upstream end of a water conduit of the third component. Similarly, air conduit  1002  may include an upstream end  1028  and a downstream end  1030  wherein upstream end  1028  is configured to couple with the downstream end of an air conduit of the second component and downstream end  1030  is configured to couple with the upstream end of an air conduit of the third component. In some examples, either or both of the second and third components may be another manifold  1000 . Additionally, or alternatively, the second component may be male adapter  930  and the third component may be female adapter  940  and/or an end cap  950 . 
     To facilitate coupling with the one or more other components, manifold  1000  further includes attachment mechanisms for securing manifold  1000  to the second and third components. The attachment mechanisms may include any suitable structures depending on the characteristics of the manifold and the other components. In some examples, water conduit  1002  and air conduit  1006  may each include attachment mechanisms configured to engage with attachment mechanisms disposed on the water and air conduits, respectively, of the second and/or third components. 
     For example, upstream end  1024  of water conduit  1002  may include one or more spring biased clips configured to couple with a retaining post, hereinafter referred to as post clips  1032 . Additionally, or alternatively, post clips  1032  may be referred to as spring-biased clips or water conduit clips. Post clips  1032  may include any suitable structure configured to couple with a retaining post disposed on the downstream end of the water conduit of the second component. For example, post clips  1032  may include a pair of flanges  1034  and a protrusion  1036  disposed on the end of each flange. Flanges  1034  may be flexibly resilient to allow the clip to flex around the retaining post and protrusions  1036  may be configured to engage with the retaining post of the second component (as shown in  FIG. 37 ). Water conduit  1002  of manifold  1000  may also include a retaining post  1038  configured to engage with the third component. 
     Retaining post  1038  may include any suitable structure configured to engage with spring-biased clips similar to post clips  1032  on the upstream end of the water conduit of the third component. For example, retaining post  1038  may include a substantially pentagonal prism having a height approximately the same as or greater than the height of the post clips. In some examples, retaining post  1038  may be disposed on a middle portion of water conduit  1002  that lies between upstream end  1024  and downstream end  1026 . In the embodiment shown in  FIGS. 32-36 , retaining post  1038  is approximately equidistant from both upstream end  1024  and downstream end  1026 . In some examples, retaining post  1038  may be disposed on any suitable portion of water conduit  1002 . 
     Air conduit  1006  of manifold  1000  also includes attachment mechanisms for engaging the air conduits of the second and third components. For example, upstream end  1028  of each air conduit  1006  may include one or more spring biased clips configured to couple with a retaining ridge, hereinafter referred to as ridge clips  1040 . Additionally, or alternatively, ridge clips  1040  may be referred to as spring-biased clips or air conduit clips. Ridge clips  1040  may include any suitable structure configured to couple with a retaining ridge disposed on the air conduit of the second component. For example, ridge clips  1040  may include a resiliently flexible support  1042  and a sloped lip  1044  which is configured to engage with the retaining ridge of the second component. 
     To couple with the third component, air conduit  1006  of manifold  1000  may also include a retaining ridge  1046 . Retaining ridge  1046  may include any suitable structure configured to engage with spring-biased clips (e.g., ridge clips) on the upstream end of the air conduit of the third component. For example, retaining ridge  1046  may include a ridge which extends around substantially the entire perimeter of the air conduit. In some examples, retaining ridge  1046  may be disposed on a middle portion of air conduit  1006  that lies between upstream end  1028  and downstream end  1030 . In the embodiment shown in  FIGS. 32-36 , retaining ridge  1046  is approximately equidistant from both upstream end  1028  and downstream end  1030 . In some examples, retaining ridge  1046  may be disposed on any suitable portion of air conduit  1006 . 
     In addition to attachment mechanisms, manifold  1000  may include any suitable structures and/or mechanisms for ensuring a water-tight seal between manifold  1000  and the second and third components. For example, both water conduit  1002  and air conduit  1006  may include one or more structures configured to hold one or more O-rings. In the embodiment shown in  FIGS. 32-36 , downstream end  1026  of water conduit  1002  includes two recesses  1048  each of which is configured to retain an O-ring  1050 . Recesses  1048  may include any suitable structure for retaining O-rings  1050  depending on the characteristics of manifold  1000  and the third component. For example, each recess  1048  may include a narrow channel disposed on downstream end  1026  and extending around the entire perimeter of the water conduit. 
     In some examples, recesses  1048  may be configured such that the outside edge of the O-ring is flush with or extends slightly beyond the surface of the downstream end of the water conduit as shown in  FIG. 32 . Allowing the O-ring to extend slightly beyond the surface of the water conduit may ensure a water tight seal by compressing the O-ring slightly between an inner surface of the water conduit of the third component and the bottom and sides of recesses  1048 . In some examples, water conduit  1002  includes two recesses  1048  to accommodate two O-rings  1050  as in  FIGS. 32-37 . In some examples, water conduit  1002  may include any suitable number of O-rings in any suitable number of recesses. 
     In the embodiment shown in  FIGS. 32-36 , downstream end  1030  of each air conduit  1006  includes a recess  1052 , configured to retain an O-ring  1054 . In some examples, air conduit  1006  may include a plurality of recesses  1052 . Recesses  1052  may include any suitable structure for retaining O-rings  1054  depending on the characteristics of manifold  1000  and the third component. For example, each recess  1052  may include a narrow channel disposed on downstream end  1030  extending around the entire perimeter of the air conduit. 
     In some examples, recesses  1052  may be configured such that the outside edge of the O-ring is flush with or extends slightly beyond the surface of the downstream end of the air conduit as shown in  FIG. 32 . Allowing the O-ring to extend slightly beyond the surface of the air conduit may ensure an air tight seal by compressing the O-ring slightly between an inner surface of the air conduit of the third component and the bottom and sides of recesses  1052 . In some examples, air conduit  1006  includes one recess  1052  to accommodate one O-ring  1054  as in  FIGS. 32-37 . In some examples, air conduit  1006  may include any suitable number of O-rings in any suitable number of recesses. 
     As shown in  FIGS. 32-37 , water conduit  1002  and air conduit  1006  may have different diameters. Water conduit  1002  and air conduit  1006  may have any suitable dimensions depending on the application and the characteristics of manifold  1000 . For example water conduit  1002  may have an outer diameter in the range of approximately 1.50 inches to approximately 3.00 inches and a wall thickness in the range of approximately 0.05 inches to approximately 0.50 inches while air conduit  1006  may have an outer diameter in the range of approximately 0.50 inches to approximately 2.00 inches and a wall thickness in the range of approximately 0.05 inches to approximately 0.50 inches. In some examples, the diameter of water conduit  1002  and the diameter of air conduit  1006  may not be constant. For example, upstream end  1024  of water conduit  1002  may have a larger diameter than downstream end  1026  of water conduit  1002  and upstream end  1028  of air conduit  1006  may have a larger diameter than downstream end  1030  of air conduit  1006 . 
     In some examples, upstream end  1024  of water conduit  1002  may have an outer diameter of approximately 2.80 inches and a wall thickness of approximately 0.12 inches and downstream end  1026  of water conduit  1002  may have an outer diameter of approximately 2.50 inches and a wall thickness of approximately 0.12 inches. In some example, upstream end  1028  of air conduit  1006  may have an outer diameter of approximately 1.23 inches and a wall thickness of approximately 0.09 inches, and downstream end  1030  of air conduit  1006  may have an outer diameter of approximately 1.00 inches and a wall thickness of approximately 0.09 inches. In some examples, upstream end  1024  and downstream end  1026  of water conduit  1002  and upstream end  1028  and downstream end  1030  of air conduit  1006  may have any suitable diameters and wall thicknesses depending on the application and the characteristics of manifold  1000  and other components. 
     O-rings  1050  and O-rings  1054  may have any suitable dimensions, materials, and/or properties. In some examples, O-rings  1050  and O-rings  1054  may have different dimensions, materials, and/or properties. For example, O-ring  1050  may be larger in diameter than O-ring  1054 . For example, O-rings  1050  may have an outer diameter between approximately 1.3 inches and approximately 3.2 inches and O-rings  1054  may have an outer diameter between approximately 0.3 inches and approximately 2.2 inches. In some examples, O-rings  1050  may have an outer diameter of approximately 2.44 inches and O-rings  1054  may have an outer diameter of approximately 0.95 inches. 
     O-rings  1050  and  1054  also may have any suitable cross-sectional diameter. For example, O-rings  1050  may have a cross-sectional diameter or thickness between approximately 0.10 inches and approximately 0.20 inches, and O-rings  1054  may have a cross-sectional diameter or thickness between approximately 0.07 inches and approximately 0.17 inches. In some examples, O-ring  1050  may have a cross-sectional diameter of approximately 0.14 inches and O-ring  1054  may have a cross-sectional diameter of approximately 0.10 inches. In some examples, O-rings  1050  and  1054  may have any suitable outer diameter and cross-sectional diameter (thickness). O-rings  1050  and  1054  may be installed on manifold  1000  prior to assembling the plumbing system. O-rings  1050  and  1054  may be constructed out of any suitable material. For example, O-rings  1050  and  1054  may be constructed out of elastomer such as any suitable thermosetting polymer and/or thermoplastic. 
     Manifold  1000 , which also may be referred to as a “manifold body,” is configured to be coupled with two other plumbing system components. Manifold  1000  may be configured to be coupled with the second and third components by a “press-and-click” method (described above). The “press-and-click” method may be facilitated by post clips  1032 , retaining posts  1038 , ridge clips  1040 , and retaining ridge  1046 . For example, manifold  1000  and the second component may be aligned and then compressed together to overcome the resistive force of ridge clips  1040  and post clips  1032 . In the embodiment shown in  FIGS. 32-37 , flanges  1034  of post clips  1032  are configured to flex apart, away from a default position (e.g., away from each other), when protrusions  1036  slide over a retaining post on the second component. Post clips  1032  are further configured to snap back into the default position (e.g., back towards each other), once protrusions  1036  pass by the retaining post on the second component. Protrusions  1036  prevent post clip  1032 , and thus manifold  1000 , from sliding off of the second component. 
     Similarly, in the embodiment shown in  FIGS. 32-37 , ridge clips  1040  are configured to flex outward, away from a default position (e.g., away from second longitudinal axis  1008 ), when sloped lip  1044  slides over a retaining ridge on the second component. Ridge clips  1040  are further configured to snap back into the default position (e.g., back towards second longitudinal axis  1008 ) once sloped lip  1044  passes over the retaining ridge on the second component. Sloped lip  1044  prevents ridge clip  1040 , and thus manifold  1000 , from sliding off of the second component. 
     Manifold  1000  may be coupled with the third component via a similar method. For example, manifold  1000  and the third component may be aligned and then compressed together to overcome the resistive force of the ridge clips and post clips of the third component. In the embodiment shown in  FIGS. 32-37 , retaining post  1038  is configured to force the spring biased clips on the air conduit of the third component (e.g., post clips  1032 ) to flex outward (e.g., away from each other) when the clips begin to slide past retaining post  1038 . Once a lip or protrusion (e.g., protrusion  1036 ) on the spring biased clips has passed retaining post  1038 , the clips snap back into the default position (e.g., back towards each other). Retaining post  1038  prevents the third component from sliding off the manifold by engaging with the lip or protrusion on the spring biased clips of the third component. 
     Similarly, in the embodiment shown in  FIGS. 32-37 , retaining ridge  1046  is configured to force the spring biased clips on the air conduit of the third component (e.g., ridge clips  1040 ) to flex outward (e.g., away from second longitudinal axis  1008 ) when the clips begin to slide over retaining ridge  1046 . Once a lip or protrusion (e.g., sloped lip  1044 ) on the spring biased clips has passed over retaining ridge  1046 , the clips snap back into the default position. Retaining ridge  1046  prevents the third component from sliding off of manifold  1000  by engaging with a lip or protrusion on the spring biased clips of the third component. 
     In some examples, manifold  1000  and the second and third components may be configured to be able to be unlocked and/or uncoupled. Uncoupling manifold  1000  from the second component may be accomplished by moving flanges  1034  of the post clips away from each other (e.g., away from the retaining post), moving ridge clips  1040  away from the air conduit (e.g., away from second longitudinal axis  1008 ), and sliding the manifold off of the second component. Uncoupling manifold  1000  from the third component may be accomplished by moving the flanges of the post clips on the third component away from each other (e.g., away from retaining post  1038 ), moving the ridge clips of the third component away from air conduit  1006 , and sliding the third component off of manifold  1000 . In some examples, a worker may accomplish this using a finger or fingers to move the clips and/or using a tool. Releasably coupling the manifold and the other components together may be advantageous as it may allow a worker to uncouple a manifold that was coupled to the wrong component by mistake. 
     Manifold  1000  may be constructed out of any suitable material. For example, manifold  1000  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). Manifold  1000  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     First Embodiment of a Male Manifold Adapter 
       FIGS. 38-40  depict various views of a first embodiment  1100  of male manifold adapter  930  which is suitable for use with manifold  1000  in manifold assembly  912 . Male manifold adapter  1100  is an example of male adapter  930  described briefly above and, along with manifold  1000 , forms part of the first embodiment of the set of manifold assembly components. Accordingly, similar components may be labeled with similar reference numbers. Additionally, or alternatively, male manifold adapter  1100  may be referred to as a male adapter. 
     Male manifold adapter  1100  is configured to couple with manifold  1000  and to provide air and water as separate streams to manifold  1000 . Accordingly, many features of male manifold adapter  1100  are substantially similar to manifold  1000 ; the primary differences between male adapter  1100  and manifold  1000  are that male adapter  1100  lacks air and water egress ports and the upstream end is configured to couple directly with air and water supply tubing. 
       FIG. 38  is an oblique isometric view of male adapter  1100 ;  FIG. 38  shows two O-rings.  FIG. 39  is a bottom plan view of male adapter  1100 .  FIG. 40  is a side elevation view of male adapter  1100 .  FIGS. 39 and 40  do not show the O-rings. 
     Male adapter  1100  includes a water conduit  1102  defining a first longitudinal axis  1104 . Water conduit  1102  may include any suitable structure configured to receive a stream of water from, for example, pipe  112 , and to deliver the stream of water to, for example, manifold  1000 . In some examples, water conduit  1102  may be a substantially cylindrical tube as in  FIGS. 38-40 . Male adapter  1100  further includes at least one air conduit  1106  defining a second longitudinal axis  1108 . Air conduit  1106  may include any suitable structure configured to receive a stream of air from, for example, air tubing  116 , and to deliver the stream of air to, for example, manifold  1000 . In some examples, air conduit  1106  may include a substantially cylindrical tube as in  FIGS. 38-40 . In this embodiment, second longitudinal axis  1108  is substantially parallel to first longitudinal axis  1104  and air conduit  1106  includes a periphery  1110  joined to a periphery  1112  of water conduit  1102  via support structure  1114 . Support structure  1114  may include any suitable structure for rigidly connecting air conduit  1106  to water conduit  1102 . For example, support structure  1114  may include a rigid strut as best seen in  FIGS. 38-39 . In some examples, second longitudinal axis  1108  may have any suitable orientation with respect to first longitudinal axis  1104  and air conduit  1106  may be joined with water conduit  1102  in any suitable manner. 
     Male adapter  1100  may include any suitable number of water conduits  1102  and air conduits  1106 . For example, male adapter  1100  may include two air conduits  1106  rigidly connected to one water conduit  1102  as best seen in  FIGS. 38-39 . In embodiments having two or more air conduits  1106 , the two or more second longitudinal axes  1108  may have any suitable disposition and/or orientation in relation to first longitudinal axis  1104 . For example, in the embodiment shown in  FIGS. 38-40 , two second longitudinal axes  1108  are disposed on either side of, and lie in a plane with, first longitudinal axis  1104 . That is, the two air conduits are disposed on opposite sides of the water conduit. In other words, in the embodiment shown in  FIGS. 38-40 , a first air conduit of the male adapter is joined to a first portion of the periphery of the water conduit of the male adapter, a second air conduit of the male adapter is joined to a second portion of the periphery of the water conduit, and the first and second portions of the periphery of the water conduit are separated from each other by approximately 180 degrees. 
     Note that since male adapter  1100  is configured to couple with manifold  1000 , male adapter  1100  generally has the same number of water conduits as manifold  1000  and the same number of air conduits as manifold  1000 . For example, in embodiments wherein manifold  1000  includes one water conduit and two air conduits, male adapter  1100  will include one water conduit and two air conduits. In examples wherein male adapter  1100  has a different number of air and/or water conduits than manifold  1000 , any suitable structure may be used to plug, seal, and/or otherwise couple with any conduits which do not couple with a conduit of the other component. 
     Male adapter  1100  may be further configured to couple with one or more components, such as with a segment of pipe  112 , a length of air tubing  116 , and with a manifold, such as manifold  1000 . For example, water conduit  1102  may include an upstream end  1116  configured to couple with pipe  112  and a downstream end  1118  configured to couple with the water conduit of manifold  1000 . Similarly, air conduit  1106  may include an upstream end  1120  configured to couple with air tubing  116  and a downstream end  1122  configured to couple with the air conduit of manifold  1000 . This description focuses on examples wherein male manifold adapter  1100  is configured to couple with a manifold such as manifold  1000 , however, in some examples, male adapter  1100  may be configured to couple with any suitable component including another adapter, any suitable style of manifold, and/or an end cap. 
     Upstream end  1116  of water conduit  1102  and upstream end  1120  of air conduit  1106  may include any suitable structures and/or mechanisms to facilitate coupling with pipe  112  and air tubing  116  respectively. In some examples, coupling with pipe  112  may include an end of pipe  112  being inserted inside upstream end  1116  of water conduit  1102 . For example, upstream end  1116  of water conduit  1102  may include a smooth inner surface and may have an inner diameter  1124  that is substantially the same as an outer diameter of pipe  112 . In some examples, inner diameter  1124  may be between approximately 1.8 inches and approximately 3.0 inches. In some examples, inner diameter  1124  may be approximately 2.3 inches and/or any other suitable size. 
     In some examples, coupling with pipe  112  may include upstream end  1116  of water conduit  1102  being inserted inside an end of pipe  112 . For example, upstream end  1116  of water conduit  1102  may include a smooth outer surface and may have an outer diameter that is substantially the same as an inner diameter of pipe  112 . In some examples, an outer diameter of upstream end  1116  may be between approximately 1.8 inches and approximately 3.0 inches. In some examples, the outer diameter of upstream end  1116  may be approximately 2.3 inches and/or any other suitable size. In the embodiment shown in  FIGS. 38-40 , upstream end  1116  is configured to fit over an end of pipe  112  and upstream end  1116  of water conduit  1102  includes a flange or ridge  1126 . In some examples, upstream end  1116  may include any suitable structure to facilitate coupling with pipe  112  and/or to improve the structural integrity of the water conduit. 
     Further, upstream end  1120  of air conduit  1106  is configured to couple with air tubing  116 . In some examples, coupling with air tubing  116  may include an end of air tubing  116  being inserted inside upstream end  1120  of air conduit  1106 . For example, upstream end  1120  of air conduit  1106  may include a smooth inner surface and may have an inner diameter  1128  that is substantially the same as an outer diameter of air tubing  116 . In some examples, inner diameter  1128  may be between approximately 0.8 inches and approximately 1.5 inches. In some examples, inner diameter  1128  may be approximately 0.9 inches and/or any other suitable size. 
     In some examples, coupling with air tubing  116  may include upstream end  1120  of air conduit  1106  being inserted inside an end of air tubing  116 . For example, upstream end  1120  of air conduit  1106  may include a smooth outer surface and may have an outer diameter that is substantially the same as an inner diameter of air tubing  116 . In some examples, an outer diameter of upstream end  1120  may be between approximately 0.8 inches and approximately 1.5 inches. In some examples, the outer diameter may be approximately 0.9 inches and/or any other suitable size. In the embodiment shown in  FIGS. 38-40 , upstream end  1120  is configured to fit over an end of air tubing  116  and upstream end  1120  of air conduit  1106  includes a smooth external surface. In some examples, upstream end  1120  may include any suitable structure to facilitate coupling with air tubing  116  and/or to improve the structural integrity of the air conduit. 
     To facilitate coupling with manifold  1000  (or any other suitable second component), male adapter  1100  further includes attachment mechanisms for securing male adapter  1100  to manifold  1000 . The attachment mechanisms may include any suitable structures depending on the characteristics of the male adapter and the manifold. In some examples, water conduit  1102  and air conduit  1106  may each include attachment mechanisms configured to engage with attachment mechanisms disposed on the water and air conduits, respectively of manifold  1000 . 
     For example, downstream end  1118  of water conduit  1102  may include a retaining post  1130  configured to engage with the manifold. Retaining post  1130  may include any suitable structure configured to engage with spring-biased clips (e.g., post clips  1032  of manifold  1000 ) on the upstream end of the water conduit of the manifold. For example, retaining post  1130  may include a substantially pentagonal prism having a height approximately the same as or greater than the height of the spring-biased clips. In some examples, retaining post  1130  may be disposed in a middle portion of water conduit  1102  that lies between upstream end  1116  and downstream end  1118  as in  FIGS. 38 and 40 . In some examples, retaining post  1130  may be approximately equidistant from both upstream end  1116  and downstream end  1118 . In some examples, retaining post  1130  may be disposed on any suitable portion of water conduit  1102 . 
     Air conduit  1106  of male adapter  1100  may also include a retaining ridge  1132 . Retaining ridge  1132  may include any suitable structure configured to engage with spring biased clips (e.g., ridge clips  1040  of manifold  1000 ) on the upstream end of the air conduit of the manifold. For example, retaining ridge  1132  may include a ridge which extends around substantially the entire perimeter of the air conduit. In some examples, retaining ridge  1132  may be disposed on a middle portion of air conduit  1106  that lies between upstream end  1120  and downstream end  1122  as in  FIGS. 38 and 40 . In some examples, retaining ridge  1132  may be approximately equidistant from both upstream end  1120  and downstream end  1122 . In some examples, retaining ridge  1132  may be disposed on any suitable portion of air conduit  1106 . 
     In addition to attachment mechanisms, male adapter  1100  may include any suitable structures and/or mechanisms for ensuring a water-tight seal between male adapter  1100  and manifold  1000  (or any other suitable second component). For example, both water conduit  1102  and air conduit  1106  include one or more structures configured to hold one or more O-rings. In the embodiment shown in  FIGS. 38-40 , downstream end  1118  of water conduit  1102  includes one or more recesses  1134 , each of which is configured to retain an O-ring  1136 . Recesses  1134  may include any suitable structure for retaining O-rings  1136  depending on the characteristics of male adapter  1100  and the second component. 
     For example, each recess  1134  may include a narrow channel disposed on downstream end  1118  and extending around the entire perimeter of the water conduit. In some examples, recesses  1134  may be configured such that the outside edge of the O-ring is flush with or extends slightly beyond the surface of the downstream end of the water conduit as shown in  FIG. 38 . Allowing the O-ring to extend slightly beyond the surface of water conduit  1102  may ensure a water tight seal by compressing the O-ring slightly between an inner surface of the water conduit of the manifold and the bottom and sides of recesses  1134 . In some examples, water conduit  1102  includes two recesses  1134  to accommodate two O-rings  1136  as in the embodiment shown in  FIGS. 38-40 . In some examples, water conduit  1102  may include any suitable number of O-rings in any suitable number of recesses. 
     In the embodiment shown in  FIGS. 38-40 , downstream end  1122  of air conduit  1106  includes a recess  1138 , configured to retain an O-ring  1140 . In some examples, air conduit  1106  may include a plurality of recesses  1138 . Recesses  1138  may include any suitable structure for retaining O-rings  1140  depending on the characteristics of male adapter  1100  and the second component. For example, each recess  1138  may include a narrow channel disposed on downstream end  1122  and extending around the entire perimeter of the air conduit. In some examples, recesses  1138  may be configured such that the outside edge of the O-ring is flush with or extends slightly beyond the surface of the downstream end of the air conduit as shown in  FIG. 38 . Allowing the O-ring to extend slightly beyond the surface of the air conduit may ensure an air tight seal by compressing the O-ring slightly between an inner surface of the air conduit of the second component and the bottom and sides of recesses  1138 . In some examples, air conduit  1106  includes one recess  1042  to accommodate one O-ring  1140  as in  FIGS. 38-40 . In some examples, air conduit  1106  may include any suitable number of O-rings in any suitable number of recesses. 
     As shown in  FIGS. 38-40 , water conduit  1102  and air conduit  1106  may have different dimensions. Water conduit  1102  and air conduit  1106  may have any suitable dimensions depending on the application and the characteristics of male adapter  1100  and manifold  1000 . Note that since male adapter  1100  is configured to couple with manifold  1000 , water conduit  1102  of male adapter  1100  generally has complimentary dimensions to the water conduit of manifold  1000  and air conduit  1106  of male adapter  1100  generally has complementary dimension to the air conduit of manifold  1000 . In other words, an outer diameter of downstream end  1118  of water conduit  1102  may be approximately the same as an inner diameter of the upstream end of the water conduit of manifold  1000 , and an outer diameter of downstream end  1122  of air conduit  1106  may be approximately the same as an inner diameter of the upstream end of the air conduit of manifold  1000 . Thus, a downstream portion of male manifold  1100  may fit within an upstream portion of manifold  1000 , forming a water tight seal. 
       FIGS. 46-47  show male manifold adapter  1100  and a manifold body  1000  coupled together.  FIG. 46  also shows a female manifold adapter  1200  coupled to another manifold body  1000 , where the two manifold bodies are coupled together.  FIG. 47  also shows an end cap coupled to another manifold body  1000 , where the two manifold bodies are coupled together. 
     Water conduit  1102  and air conduit  1106  may have any suitable dimensions depending on the application and the characteristics of male adapter  1100  and manifold  1000 . For example, water conduit  1102  may have an outer diameter in the range of approximately 1.50 inches to approximately 3.00 inches and a wall thickness in the range of approximately 0.05 inches to approximately 0.50 inches while air conduit  1106  may have an outer diameter in the range of approximately 0.50 inches to approximately 2.00 inches and a wall thickness in the range of approximately 0.05 inches to approximately 0.50 inches. 
     In some examples, the diameter of water conduit  1102  and the diameter of air conduit  1106  may not be constant. For example, upstream end  1116  of water conduit  1102  may have a larger diameter than downstream end  1118  of water conduit  1102  and upstream end  1120  of air conduit  1106  may have a larger diameter than downstream end  1122  of air conduit  1106 . In some examples, upstream end  1116  of water conduit  1102  may have an outer diameter of approximately 2.80 inches and a wall thickness of approximately 0.12 inches and downstream end  1118  of water conduit  1102  may have an outer diameter of approximately 2.60 inches and a wall thickness of approximately 0.12 inches. In some examples, upstream end  1120  of air conduit  1106  may have an outer diameter of approximately 1.14 inches and a wall thickness of approximately 0.09 inches, and downstream end  1122  of air conduit  1106  may have an outer diameter of approximately 1.00 inches and a wall thickness of approximately 0.09 inches. In some examples, upstream end  1116  and downstream end  1118  of water conduit  1102  and upstream end  1120  and downstream end  1122  of air conduit  1106  may have any suitable diameters and wall thicknesses depending on the application and the characteristics of male adapter  1100 , manifold  1000 , and other components. 
     O-rings  1136  and O-rings  1140  may have any suitable dimensions, materials, and/or properties. In some examples, O-rings  1136  and O-rings  1140  may have different dimensions, materials, and/or properties. In some examples, O-rings  1136  may be substantially identical to O-rings  1050  on manifold  1000 . In some examples, O-rings  1140  may be substantially identical to O-rings  1054  on manifold  1000 . O-ring  1136  may be larger in diameter than O-ring  1140 . For example, O-rings  1136  may have an outer diameter between approximately 1.3 inches and approximately 3.2 inches and O-rings  1140  may have an outer diameter between approximately 0.3 inches and approximately 2.2 inches. In some examples, O-rings  1136  may have an outer diameter of approximately 2.44 inches and O-rings  1140  may have an outer diameter of approximately 0.95 inches. 
     O-rings  1136  and  1140  may have any suitable cross-sectional diameter. For example, O-rings  1136  may have a cross-sectional diameter or thickness between approximately 0.10 inches and approximately 0.20 inches, and O-rings  1140  may have a cross-sectional diameter or thickness between approximately 0.07 inches and approximately 0.17 inches. In some examples, O-ring  1136  may have a cross-sectional diameter of approximately 0.14 inches and O-ring  1140  may have a cross-sectional diameter of approximately 0.10 inches. In some examples, O-rings  1136  and  1140  may have any suitable outer diameter and cross-sectional diameter (thickness). O-rings  1136  and  1140  may be installed on male adapter  1100  prior to assembling the plumbing system. O-rings  1136  and  1140  may be constructed out of any suitable material. For example, O-rings  1136  and  1140  may be constructed out of elastomer such as any suitable thermosetting polymer and/or thermoplastic. 
     As discussed, male adapter  1100  is configured to be coupled with another component such as manifold  1000 . Male adapter  1100  may be configured to be coupled with the second component by a “press-and-click” method (described above). The “press-and-click” method may be facilitated by retaining post  1130  and retaining ridge  1132 . For example, male adapter  1100  and the manifold may be aligned and then compressed together to overcome the resistive force of one or more spring biased clips on the manifold (e.g., ridge clips  1040  and post clips  1032 ), after which the components are locked together. 
     For example, retaining post  1130  may be configured to couple with the manifold by engaging with suitably configured spring biased clips. For example, in the embodiment shown in  FIGS. 38-40 , retaining post  1130  is configured to force the spring biased clips on the air conduit of the manifold (e.g., post clips  1032 ) to flex outward (e.g., away from each other) when the clips begin to slide past retaining post  1130 . Once a lip or protrusion (e.g., protrusion  1036 ) on the spring biased clips has passed retaining post  1130 , the clips snap back into the default position (e.g., back towards each other). Retaining post  1130  prevents the manifold from sliding off of the male adapter by engaging with the lip or protrusion on the spring biased clips on the manifold. 
     Similarly, retaining ridge  1132  may be configured to couple with the manifold by engaging with suitably configured spring biased clips. For example, in the embodiment shown in  FIGS. 38-40 , retaining ridge  1132  is configured to force the spring biased clips on the air conduit of manifold  1000  (e.g., ridge clips  1040 ) to flex outward (e.g., away from second longitudinal axis  1108 ) when the clips begin to slide over retaining ridge  1132 . Once a lip or protrusion (e.g., sloped lip  1044 ) on the spring biased clips has passed over retaining ridge  1132 , the clips snap back into the default position. Retaining ridge  1132  prevents the manifold from sliding off of the male adapter by engaging with a lip or protrusion on the spring biased clips on the manifold. 
     In some examples, male adapter  1100  and manifold  1000  (or any other suitable second component) may be configured to be able to be unlocked and/or uncoupled. Uncoupling the manifold from male adapter  1100  may be accomplished by moving the flanges of the post clips on the manifold away from each other (e.g., away from retaining post  1130 ), moving the ridge clips on the manifold away from air conduit  1106  (e.g., away from second longitudinal axis  1108 ), and sliding the manifold off of male adapter  1100 . In some examples, a worker may accomplish this using a finger or fingers to move the clips and/or using a tool. Releasably coupling male adapter  1100  and the manifold together may be advantageous as it may allow a worker to uncouple a manifold that was couple to the wrong male adapter by mistake. 
     Male adapter  1100  may be constructed out of any suitable material. For example, male adapter  1100  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). Male adapter  1100  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     First Embodiment of a Female Manifold Adapter 
       FIGS. 41-43  depict various views of a first embodiment  1200  of female manifold adapter  940  which is suitable for use with manifold  1000  in manifold assembly  912 . Female manifold adapter  1200  is an example of female adapter  940  described briefly above and, along with manifold  1000  and male adapter  1100 , forms part of the first embodiment of the set of manifold assembly components. Accordingly, similar components may be labeled with similar reference numbers. Additionally, or alternatively, female manifold adapter  1200  may be referred to as a female adapter. 
     Female manifold adapter  1200  is configured to couple with manifold  1000  and to receive air and water as separate streams from manifold  1000 . Accordingly, many features of female manifold adapter  1200  are substantially similar to manifold  1000 ; the primary differences between female adapter  1200  and manifold  1000  are that female adapter  1200  lacks air and water egress ports and the downstream end is configured to couple directly with air and water supply tubing. 
       FIG. 41  is an oblique isometric view of female adapter  1200 .  FIG. 42  is a bottom plan view of female adapter  1200 .  FIG. 43  is a side elevation view of female adapter  1200 . 
     Female adapter  1200  includes a water conduit  1202  defining a first longitudinal axis  1204 . Water conduit  1202  may include any suitable structure configured to receive a stream of water from, for example, manifold  1000  and to deliver the stream of water to, for example, pipe  112 . In some examples, water conduit  1202  may be a substantially cylindrical tube as in  FIGS. 41-43 . Female adapter  1200  further includes at least one air conduit  1206  defining a second longitudinal axis  1208 . Air conduit  1206  may include any suitable structure configured to receive a stream of air from, for example, manifold  1000 , and to deliver the stream of air to, for example, air tubing  116 . 
     In some examples, air conduit  1206  may include a substantially cylindrical tube as in  FIGS. 41-43 . In this embodiment, second longitudinal axis  1208  is substantially parallel to first longitudinal axis  1204  and air conduit  1206  includes a periphery  1210  joined to a periphery  1212  of water conduit  1202  via support structure  1214 . Support structure  1214  may include any suitable structure for rigidly connecting air conduit  1206  to water conduit  1202 . For example, support structure  1214  may include a rigid strut as best seen in  FIGS. 41-43 . In some examples, second longitudinal axis  1208  may have any suitable orientation with respect to first longitudinal axis  1204  and air conduit  1206  may be joined with water conduit  1202  in any suitable manner. 
     Female adapter  1200  may include any suitable number of water conduits  1202  and air conduits  1206 . For example, female adapter  1200  may include two air conduits  1206  rigidly connected to one water conduit  1202  as best seen in  FIGS. 41-43 . In embodiments having two or more air conduits  1206 , the two or more second longitudinal axes  1208  may have any suitable disposition and/or orientation in relation to first longitudinal axis  1204 . For example, in the embodiment shown in  FIGS. 41-43 , two second longitudinal axes  1208  are disposed on either side of, and lie in a plane with, first longitudinal axis  1204 . That is, the two air conduits are disposed on opposite sides of the water conduit. In other words, in the embodiment shown in  FIGS. 41-43 , a first air conduit of the female adapter is joined to a first portion of the periphery of the water conduit of the female adapter, a second air conduit of the female adapter is joined to a second portion of the periphery of the water conduit, and the first and second portions of the periphery of the water conduit are separated from each other by approximately 180 degrees. 
     Note that since female adapter  1200  is configured to couple with manifold  1000 , female adapter  1200  generally has the same number of water conduits as manifold  1000  and the same number of air conduits as manifold  1000 . For example, in embodiments wherein manifold  1000  includes one water conduit and two air conduits, female adapter  1200  will include one water conduit and two air conduits. In examples wherein female adapter  1200  has a different number of air and/or water conduits than manifold  1000 , any suitable structure may be used to plug, seal, and/or otherwise couple with any conduits which do not couple with a conduit of the other component. 
     Female adapter  1200  may be further configured to couple with one or more components, such as a manifold (for example, manifold  1000 ), a segment of pipe  112 , and a length of air tubing  116 . For example, water conduit  1202  may include an upstream end  1216  configured to couple with the water conduit of manifold  1000  and a downstream end  1218  configured to couple with pipe  112 . Similarly, air conduit  1206  may include an upstream end  1220  configured to couple with the air conduit of manifold  1000  and a downstream end  1122  configured to couple with air tubing  116 . This description focuses on examples wherein female manifold adapter  1200  is configured to couple with a manifold such as manifold  1000 , however, in some examples, female adapter  1200  may be configured to couple with any suitable component including another adapter and/or any suitable style of manifold. 
     To facilitate coupling with manifold  1000  (or any other suitable component), female adapter  1200  further includes attachment mechanisms for securing female adapter  940  to manifold  1000 . The attachment mechanisms may include any suitable structures depending on the characteristics of the adapter, the manifold, and/or other components. In some examples, water conduit  1202  and air conduit  1206  may each include attachment mechanisms to engage with attachment mechanisms disposed on the water and air conduits, respectively, of the manifold. 
     For example, upstream end  1216  of water conduit  1202  may include one or more spring biased clips configured to couple with a retaining post, hereinafter referred to as post clips  1228 . Additionally, or alternatively, post clips  1228  may be referred to as spring-biased clips or water conduit clips. Post clips  1228  may include any suitable structure configured to couple with a retaining post disposed on the downstream end of the water conduit of the manifold. For example, post clips  1228  may include a pair of flanges  1230  and a protrusion or lip  1232  disposed on the end of each flange  1230 . Flanges  1230  may be flexibly resilient to allow the clip to flex around the retaining post and protrusions FF 24  may be configured to engage with the retaining post of the manifold (as shown in  FIG. 46 ). 
     Air conduit  1206  of female adapter  1200  also includes attachment mechanisms for engaging with the air conduit of the manifold (or any other suitable component). For example, upstream end  1220  of each air conduit  1206  may include one or more spring biased clips configured to couple with a retaining ridge, hereinafter referred to as ridge clips  1234 . Additionally, or alternatively, ridge clips  1234  may be referred to as spring-biased clips or air conduit clips. Ridge clips  1234  may include any suitable structure configured to couple with a retaining ridge disposed on the air conduit of the manifold. For example, ridge clips  1234  may include a resiliently flexible support  1236  and a sloped lip  1238  which is configured to engage with the retaining ridge on the manifold. 
     Downstream end  1218  of water conduit  1202  and downstream end  1222  of air conduit  1206  may include any suitable structures and/or mechanisms to facilitate coupling with pipe  112  and air tubing  116  respectively. In some examples, coupling with pipe  112  may include an end of pipe  112  being inserted inside downstream end  1218  of water conduit  1202 . For example, downstream end  1218  of water conduit  1202  may include a smooth inner surface and may have an inner diameter  1224  that is substantially the same as an outer diameter of pipe  112 . In some examples, inner diameter  1224  may be between approximately 1.8 inches and approximately 3.0 inches. In some examples, inner diameter  1224  may be approximately 2.12 inches and/or any other suitable size. In some examples, coupling with pipe  112  may include downstream end  1218  of water conduit  1202  being inserted inside an end of pipe  112 . 
     For example, downstream end  1218  of water conduit  1202  may include a smooth outer surface and may have an outer diameter that is substantially the same as an inner diameter of pipe  112 . In some examples, an outer diameter of downstream end  1218  may be between approximately 1.8 inches and approximately 3.0 inches. In some examples, the outer diameter may be approximately 2.12 inches and/or any other suitable size. In some examples, downstream end  1218  of water conduit  1202  may include any suitable structure to facilitate coupling with pipe  112  and/or to improve the structural integrity of the water conduit. In some examples, downstream end  1218  of water conduit  1202  may include a flange or ridge. 
     Further, downstream end  1222  of air conduit  1206  is configured to couple with air tubing  116 . In some examples, coupling with air tubing  116  may include an end of air tubing  116  being inserted inside downstream end  1222  of air conduit  1206 . For example, downstream end  1222  of air conduit  1206  may include a smooth inner surface and may have an inner diameter  1226  that is substantially the same as an outer diameter of air tubing  116 . In some examples, inner diameter  1226  may be between approximately 0.50 inches and approximately 1.50 inches. In some examples, inner diameter  1226  may be approximately 0.88 inches and/or any other suitable size. 
     In some examples, coupling with air tubing  116  may include downstream end  1222  of air conduit  1206  being inserted inside an end of air tubing  116 . For example, downstream end  1222  of air conduit  1206  may include a smooth outer surface and may have an outer diameter that is substantially the same as an inner diameter of air tubing  116 . In some examples, an outer diameter of downstream end  1222  may be between approximately 0.50 inches and approximately 1.50 inches. In some examples, the outer diameter may be approximately 0.88 inches and/or any other suitable size. In the embodiment shown in  FIGS. 41-43 , downstream end  1222  of air conduit  1206  includes a smooth external surface. In some examples, downstream end  1222  may include any suitable structure to facilitate coupling with air tubing  116  and/or to improve the structural integrity of the air conduit. 
     In addition to attachment mechanisms, female adapter  1200  may include any suitable structures and/or mechanisms for ensuring a water-tight seal between female adapter  1200  and pipe  112 , air tubing  116 , and/or manifold  1000  (or any other suitable second component). In some examples, female adapter  1200  may include structures for holding and/or engaging with O-rings and/or any other suitable mechanical seal. 
     As shown in  FIGS. 41-43 , water conduit  1202  and air conduit  1206  may have different dimensions. Water conduit  1202  and air conduit  1206  may have any suitable dimensions depending on the application and the characteristics of female adapter  1200  and manifold  1000 . Note that since female adapter  1200  is configured to couple with manifold  1000 , water conduit  1202  of female adapter  1200  generally has complimentary dimensions to the water conduit of manifold  1000  and air conduit  1206  of female adapter  1200  generally has complementary dimension to the air conduit of manifold  1000 . In other words, an inner diameter of upstream end  1216  of water conduit  1202  may be approximately the same as an outer diameter of the downstream end of the water conduit of manifold  1000 , and an inner diameter of upstream end  1220  of air conduit  1206  may be approximately the same as an outer diameter of the downstream end of the air conduit of manifold  1000 . Thus, a downstream portion of manifold  1000  may fit within an upstream portion of female manifold  1200 , forming a water tight seal.  FIG. 46  shows female manifold adapter  1200  and manifold  1000  coupled together. 
     Water conduit  1202  and air conduit  1206  may have any suitable diameters depending on the application and the characteristics of female adapter  1200  and manifold  1000 . For example, water conduit  1202  may have an outer diameter in the range of approximately 1.50 inches to approximately 3.00 inches and a wall thickness in the range of approximately 0.05 inches to approximately 0.50 inches while air conduit  1206  may have an outer diameter in the range of approximately 0.50 inches to approximately 2.00 inches and a wall thickness in the range of approximately 0.05 inches to approximately 0.50 inches. 
     In some examples, the diameter of water conduit  1202  and the diameter of air conduit  1206  may not be constant. For example, upstream end  1216  of water conduit  1202  may have a larger diameter than downstream end  1218  of water conduit  1202  and upstream end  1220  of air conduit  1206  may have a larger diameter than downstream end  1222  of air conduit  1206 . In some examples, upstream end  1216  of water conduit  1202  may have an outer diameter of approximately 2.81 inches and a wall thickness of approximately 0.14 inches and downstream end  1218  of water conduit  1202  may have an outer diameter of approximately 2.73 inches and a wall thickness of approximately 0.14 inches. In some example, upstream end  1220  of air conduit  1206  may have an outer diameter of approximately 1.23 inches and a wall thickness of approximately 0.11 inches, and downstream end  1222  of air conduit  1206  may have an outer diameter of approximately 1.09 inches and a wall thickness of approximately 0.11 inches. In some examples, upstream end  1216  and downstream end  1218  of water conduit  1202  and upstream end  1220  and downstream end  1222  of air conduit  1206  may have any suitable diameters and wall thicknesses depending on the application and the characteristics of female adapter  1200 , manifold  1000 , and other components. 
     As discussed, female adapter  1200  is configured to be coupled with another component such as manifold  1000 . Female adapter  1200  may be configured to be coupled with the second component by a “press-and-click” method (described above). The “press-and-click” method may be facilitated by post clips  1228  and ridge clips  1234 . For example, female adapter  1200  and the manifold may be aligned and then compressed together to overcome the resistive force of post clips  1228  and ridge clips  1234 , after which the components are locked together. 
     In the embodiment shown in  FIGS. 41-43 , flanges  1230  of post clips  1228  are configured to flex apart, away from a default position (e.g., away from each other), when protrusions  1232  slide over a retaining post on the manifold. Post clips  1228  are further configured to snap back into the default position (e.g., back towards each other), once protrusions  1232  pass by the retaining post on the manifold. Protrusions  1232  prevent post clip  1228 , and thus female adapter  1200 , from sliding off of the manifold. Similarly, in the embodiment shown in  FIGS. 41-43 , ridge clips  1234  are configured to flex outward, away from a default position (e.g., away from second longitudinal axis  1208 ), when sloped lip  1238  slides over a retaining ridge on the manifold. Ridge clips  1234  are further configured to snap back into the default position (e.g., back towards second longitudinal axis  1208 ) once sloped lip  1238  passes over the retaining ridge on the manifold. Sloped lip  1238  prevents ridge clip  1234 , and thus female adapter  1200 , from sliding off of the manifold. 
     In some examples, female adapter  1200  and manifold  1000  (or any other suitable second component) may be configured to be able to be unlocked and/or uncoupled. Uncoupling female adapter  1100  from the manifold may be accomplished by moving flanges  1230  of post clips  1228  away from each other (e.g., away from the retaining post on the manifold), moving ridge clips  1234  away from the air conduit of the manifold (e.g., away from second longitudinal axis  1208 ), and sliding female adapter  1200  off of manifold  1000 . In some examples, a worker may accomplish this using a finger or fingers to move the clips and/or using a tool. Releasably coupling female adapter  1200  and the manifold together may be advantageous as it may allow a worker to uncouple a female adapter that was coupled to the wrong manifold by mistake. 
     Female adapter  1200  may be constructed out of any suitable material. For example, female adapter  1200  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). Female adapter  1200  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     First Embodiment of a Manifold End Cap 
       FIGS. 44-45  depict various views of a first embodiment  1300  of manifold end cap suitable for use with manifold  1000  in manifold assembly  912 . Manifold end cap  1300  is an example of manifold end cap  950  described briefly above with respect to  FIG. 31 . Together, manifold end cap  1300 , manifold  1000 , male adapter  1100 , and female adapter  1200  form the first set of manifold assembly components. Accordingly, similar components may be labeled with similar reference numbers. Additionally, or alternatively, manifold end cap  1300  may be referred to as an end cap. 
     End cap  1300  is configured to couple with manifold  1000  and end the streams of air and water from manifold  1000  while ensuring that the streams of air and water remain separate. Accordingly, many features of end cap  1300  are substantially similar to manifold  1000 ; the primary differences between end cap  1300  and manifold  1000  are that end cap  1300  lacks air and water egress ports and the downstream end is configured to end the streams of air and water. 
       FIG. 44  is an oblique isomeric view of end cap  1300 .  FIG. 45  is a bottom plan view of end cap  1300 . 
     End cap  1300  includes a water closure  1302  defining a first longitudinal axis  1304 . Water closure  1302  may include any suitable structure configured to couple with a water conduit of manifold  1000  and to end the flow of water. In some examples, water closure  1302  may include a substantially cylindrical tube portion which ends in a cap as in  FIG. 44 . End cap  1300  further includes at least one air closure  1306  defining a second longitudinal axis  1308 . Air closure  1306  may include any suitable structure configured to couple with an air conduit of manifold  1000  and to end the flow of air. In some examples, air closure  1306  may include a substantially cylindrical tube portion which ends in a cap as in  FIG. 44 . 
     In this embodiment, second longitudinal axis  1308  is substantially parallel to first longitudinal axis  1304  and air closure  1306  includes a periphery  1310  joined to a periphery  1312  of water closure  1302  via support structure  1314 . Support structure  1314  may include any suitable structure for rigidly connecting air closure  1306  to water closure  1302 . For example, support structure  1314  may include a rigid strut as seen in  FIGS. 44 and 45 . In some examples, second longitudinal axis  1308  may be any suitable orientation with respect to first longitudinal axis  1304  and air closure  1306  may be joined with water closure  1302  in any suitable manner. 
     End cap  1300  may include any suitable number of water closure  1302  and air closure  1306 . For example, end cap  1300  may include two air closure  1306  rigidly connected to one water closure  1302  as in  FIGS. 44-45 . In embodiments having two or more air closure  1306 , the two or more second longitudinal axes  1308  may have any suitable disposition and/or orientation in relation to first longitudinal axis  1304 . For example, in the embodiment shown in  FIGS. 44-45 , two second longitudinal axes  1308  are disposed on either side of, and lie in a plane with, first longitudinal axis  1304 . That is, the two air closures are disposed on opposite sides of the water closure. In other words, in the embodiment shown in  FIGS. 44-45 , a first air closure of the end cap is joined to a first portion of the periphery of the water closure of the end cap, a second air closure of the end cap is joined to a second portion of the periphery of the water closure, and the first and second portions of the periphery of the water closure are separated from each other by approximately 180 degrees. 
     Note that since end cap  1300  is configured to couple with manifold  1000 , end cap  1300  generally has a number of water closures that is equal to the number of water conduits on manifold  1000  and a number of air closures that is equal to the number of air conduits on manifold  1000 . For example, in embodiments wherein manifold  1000  includes one water conduit and two air conduits, end cap  1300  will include one water closure and two air closures. In examples wherein end cap  1300  has a different number of air and/or water conduits than manifold  1000 , any suitable structure may be used to plug, seal, and/or otherwise couple with any conduits of the manifold which do not couple with a closure of the end cap. 
     End cap  1300  may be configured to couple with one or more components, such as a manifold (for example, manifold  1000 ). For example, water closure  1302  may include an upstream end  1316  configured to couple with the water conduit of manifold  1000 . Similarly, air closure  1306  may include an upstream end  1318  configured to couple with the air conduit of manifold  1000 . This description focuses on examples wherein end cap  1300  is configured to couple with a manifold such as manifold  1000 , however, in some examples, end cap  1300  may be configured to couple with any suitable component including an adapter, a manifold, a water pipe, air tubing, and/or any other suitable component. 
     Further, water closure  1302  includes a downstream end  1320  configured to end the flow of water and to seal the water passageway. For example, downstream end  1320  may include a water cap  1322 . Similarly, air closure  1306  includes a downstream end  1324  configured to end the flow of air and to seal the air passageway. For example, downstream end  1324  may include an air cap  1326 . Water cap  1322  and air cap  1326  may include substantially similar structures; the primary difference between water cap  1322  and air cap  1326  may be the size of each cap. Water cap  1322  and air cap  1326  may include any suitable structure for ending the flows of water and air respectively. In some examples, water cap  1322  and air cap  1326  may be slightly convex and/or curved outward from the interior of the water and air conduits of the manifold. Such a curvature may increase the structural integrity of the end cap and/or may fit a chosen aesthetic. In some examples, water cap  1322  and air cap  1326  may be flat. 
     To facilitate coupling with manifold  1000  (or any other suitable component), end cap  1300  further includes attachment mechanisms for securing end cap  1300  to manifold  1000 . The attachment mechanisms may include any suitable structures depending on the characteristics of the end cap, the manifold, and/or other components. In some examples, water closure  1302  and air closure  1306  may each include attachment mechanisms to engage with attachment mechanisms disposed on the water and air conduits, respectively, of the manifold. 
     For example, upstream end  1316  of water closure  1302  may include one or more spring biased clips configured to couple with a retaining post, hereinafter referred to as post clips  1328 . Additionally, or alternatively, post clips  1328  may be referred to as spring-biased clips or water closure clips. Post clips  1328  may include any suitable structure configured to couple with a retaining post disposed on the downstream end of the water conduit of the manifold. For example, post clips  1328  may include a pair of flanges  1330  and a protrusion or lip  1332  disposed on the end of each flange  1330 . Flanges  1330  may be flexibly resilient to allow the clip to flex around the retaining post and protrusions  1332  may be configured to engage with the retaining post of the manifold (as shown in  FIG. 47 ). 
     Air closure  1306  of end cap  1300  also includes attachment mechanisms for engaging with the air conduit of the manifold (or any other suitable component). For example, upstream end  1318  of each air closure  1306  may include one or more spring biased clips configured to couple with a retaining ridge, hereinafter referred to as ridge clips  1334 . Additionally, or alternatively, ridge clips  1334  may be referred to as spring-biased clips or air conduit clips. Ridge clips  1334  may include any suitable structure configured to couple with a retaining ridge disposed on the air conduit of the manifold. For example, ridge clips  1334  may include a resiliently flexible support  1336  and a sloped lip  1338  which is configured to engage with the retaining ridge on the manifold. 
     In addition to attachment mechanisms, end cap  1300  may include any suitable structures and/or mechanisms for ensuring a water-tight seal between end cap  1300  and manifold  1000  (or any other suitable second component). In some examples, end cap  1300  may include structures for holding and/or engaging with O-rings and/or any other suitable mechanical seal. 
     End cap  1300  may further include a water plug  1340  and an air plug  1342 . Water plug  1340  and air plug  1342  may include any suitable structure configured to seal off unused egress ports on manifold  1000 . For example, if hot tub  100  includes an odd number of jets, one set of egress ports  1022  on manifold  1000  may not be coupled to tubing  120 . To ensure that the plumbing system is sealed, the unused set of egress ports must be plugged. In the embodiment shown in  FIGS. 44-45 , end cap  1300  includes removable water plug  1340  and removable air plug  1342 . In use, water plug  1340  and air plug  1342  may be removed from end cap  1300  and used to seal the unused set of egress ports on manifold  1000 . Removing water plug  1340  and air plug  1342  from end cap  1300  may include cutting and/or breaking a support strut  1344  which attaches the plug to end cap  1300 . In some examples, cutting and/or breaking support strut  1344  may be accomplished using any suitable tool such as scissors, wire cutters, and/or a knife. In some examples, water plug  1340  and air plug  1342  may be removed from end cap  1300  without the use of a tool. For example, support strut  1344  may be configured to tear and/or break when twisted, bent, and/or pulled. 
     Water plug  1340  may include any suitable structure configured to seal an unused water egress port. For example, water plug  1340  may include a substantially cylindrical stopper. A diameter of water plug  1340  may be approximately the same as an inner diameter of water egress port  1016 . Water plug  1340  may include a flange  1346  configured to prevent the water plug from sliding too far into water egress port  1016 . In some examples, water plug  1340  may be press fit into water egress port  1016 . In some examples, the friction between water plug  1340  and the inside of water egress port  1016  may be sufficient to hold the water plug in place. In some examples, sealing water egress port  1016  with water plug  1340  may include applying glue, primer, and/or any suitable adhesive to the outside of water plug  1340  and/or the inside of water egress port  1016 . In some examples, water plug  1340  may include a water cap which fits over the outside of water egress port  1016  and is held in place by friction and/or an adhesive. 
     Air plug  1342  may include any suitable structure configured to seal an unused air egress port. For example, air plug  1342  may include a substantially cylindrical stopper. A diameter of air plug  1342  may be approximately the same as an inner diameter of air egress port  1018 . Air plug  1342  may include a flange  1348  configured to prevent the air plug from sliding too far into air egress port  1018 . In some examples, air plug  1342  may be press fit into air egress port  1018 . In some examples, the friction between air plug  1342  and the inside of air egress port  1018  may be sufficient to hold the air plug in place. In some examples, the air system is under vacuum and vacuum pressure holds the air plug in place. In some examples, sealing air egress port  1018  with air plug  1342  may include applying glue, primer, and/or any suitable adhesive to the outside of air plug  1342  and/or the inside of air egress port  1018 . In some examples, air plug  1342  may include an air cap which fits over the outside of air egress port  1018  and is held in place by friction, vacuum pressure, and/or an adhesive. 
     As shown in  FIGS. 44-45 , water closure  1302  and air closure  1306  may have different dimensions. Water closure  1302  and air closure  1306  may have any suitable dimensions depending on the application and the characteristics of end cap  1300  and manifold  1000 . Note that since end cap  1300  is configured to couple with manifold  1000 , water closure  1302  of end cap  1300  generally has complimentary dimensions to the water conduit of manifold  1000  and air closure  1306  of end cap  1300  generally has complementary dimension to the air conduit of manifold  1000 . In other words, an inner diameter of upstream end  1316  of water closure  1302  may be approximately the same as an outer diameter of the downstream end of the water conduit of manifold  1000 , and an inner diameter of upstream end  1318  of air closure  1306  may be approximately the same as an outer diameter of the downstream end of the air conduit of manifold  1000 . Thus, a downstream portion of manifold  1000  may fit within an upstream portion of end cap  1300 , forming a water tight seal.  FIG. 47  shows end cap  1300  and manifold  1000  coupled together. 
     Water closure  1302  and air closure  1306  may have any suitable diameters depending on the application and the characteristics of end cap  1300  and manifold  1000 . In some examples, the diameter of water closure  1302  and the diameter of air closure may not be constant. For example, water closure  1302  may have an outer diameter in the range of approximately 1.50 inches to approximately 3.00 inches and a wall thickness in the range of approximately 0.05 inches to approximately 0.50 inches while air closure  1306  may have an outer diameter in the range of approximately 0.50 inches to approximately 2.00 inches and a wall thickness in the range of approximately 0.05 inches to approximately 0.50 inches. In some examples, water closure  1302  may have an outer diameter of approximately 2.81 inches and a wall thickness of approximately 0.17 inches. In some example, air closure  1306  may have an outer diameter of approximately 1.24 inches and a wall thickness of approximately 0.14 inches. In some examples, water closure  1302  and air closure  1306  may have any suitable diameters and wall thicknesses depending on the application and the characteristics of end cap  1300 , manifold  1000 , and other components. 
     As discussed, end cap  1300  is configured to be coupled with another component such as manifold  1000 . End cap  1300  may be configured to be coupled with the manifold by a “press-and-click” method (described above). The “press-and-click” method may be facilitated by post clips  1328  and ridge clips  1334 . For example, end cap  1300  and the manifold may be aligned and then compressed together to overcome the resistive force of post clips  1328  and ridge clips  1334 , after which the components are locked together. In the embodiment shown in  FIGS. 44-45 , flanges  1330  of post clips  1328  are configured to flex apart, away from a default position (e.g., away from each other), when protrusions  1332  slide over a retaining post on the manifold. Post clips  1328  are further configured to snap back into the default position (e.g., back towards each other), once protrusions  1332  pass by the retaining post on the manifold. Protrusions  1332  prevent post clip  1328 , and thus end cap  1300 , from sliding off of the manifold. Similarly, in the embodiment shown in  FIGS. 44-45 , ridge clips  1334  are configured to flex outward, away from a default position (e.g., away from second longitudinal axis  1308 ), when sloped lip  1338  slides over a retaining ridge on the manifold. Ridge clips  1334  are further configured to snap back into the default position (e.g., back towards second longitudinal axis  1308 ) once sloped lip  1338  passes over the retaining ridge on the manifold. Sloped lip  1338  prevents ridge clip  1334 , and thus end cap  1300 , from sliding off of the manifold. 
     In some examples, end cap  1300  and manifold  1000  (or any other suitable second component) may be configured to be able to be unlocked and/or uncoupled. Uncoupling end cap  1300  from the manifold may be accomplished by moving flanges  1330  of post clips  1328  away from each other (e.g., away from the retaining post on the manifold), moving ridge clips  1334  away from the air conduit of the manifold (e.g., away from second longitudinal axis  1308 ), and sliding end cap  1300  off of manifold  1000 . In some examples, a worker may accomplish this using a finger or fingers to move the clips and/or using a tool. Releasably coupling end cap  1300  and the manifold together may be advantageous as it may allow a worker to uncouple an end cap that was coupled to the wrong manifold by mistake. 
     End cap  1300  may be constructed out of any suitable material. For example, end cap  1300  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). End cap  1300  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     First Illustrative Manifold Assembly 
     Together, manifold  1000 , male manifold adapter  1100 , female manifold adapter  1200 , and manifold end cap  1300 , described above, form a first embodiment of a set of manifold assembly components. Male adapter  1100 , one or more manifolds  1000 , and female adapter  1200  or end cap  1300  may couple to form manifold assembly  912 . 
     In general, manifold assembly  912  is composed of any suitable number of each of the components in the first set of manifold assembly components and may include any suitable structures configured to separately convey air and water from respective air and water sources to a plurality of lengths of tubing  120 . For example, manifold assembly  912  may include male adapter  1100 , any suitable number of manifolds  1000 , and female adapter  1200  or end cap  1300  depending on the application. In some examples, hot tub  100  may include any suitable number of manifold assemblies  912 . In some examples, it may be advantageous to have a plurality of clusters of manifolds spaced out at different portions of hot tub  100  to better reach each jet with the least amount of tubing. Accordingly, any suitable number of manifolds  1000  grouped in any suitable number and/or size of manifold assembly  912  may be used. Each manifold assembly  912  may include any suitable number of manifolds  1000 . In some examples, manifold assembly  912  may not include female adapter  1200  and/or end cap  1300 . For example, some manifold assemblies  912  may include female adapter  1200  and not end cap  1300 , and some manifold assemblies  912  may include end cap  1300  and not female adapter  1200 . 
     As discussed,  FIG. 31  is a block diagram which includes two illustrative manifold assemblies  910  and depicts two examples of how manifold assembly  910  may interact with other plumbing components.  FIGS. 48 through 51  depict various examples of illustrative manifold assemblies; each figure may be a different view, and may include different manifold components. 
       FIG. 48  depicts an exploded isometric view of an example of first illustrative manifold assembly which includes male adapter  1100 , two manifolds or manifold bodies  1000 , and female adapter  1200 .  FIG. 49  depicts a partially exploded isometric view of another example of an illustrative manifold assembly which includes male adapter  1100 , two manifolds  1000 , and end cap  1300 .  FIG. 50  depicts a sectional isometric view of the exemplary assembly of  FIG. 48 ; and  FIG. 51  depicts another sectional isometric view of the exemplary assembly of  FIG. 48 . 
     In each of the examples of manifold assembly  912 , male adapter  1100  is in fluid communication with manifold  1000 . Each manifold  1000  is in fluid communication with another manifold  1000 , female adapter  1200 , and/or end cap  1300 . Some examples of manifold assembly  912  include female adapter  1200  ( FIGS. 48, 50, and 51 ) and some examples of manifold assembly  912  include end cap  1300  ( FIG. 49 ). Alternate use of female adapter  1200  and end cap  1300  may be advantageous as manifold assemblies which include a female adapter allow the streams of air and water to continue on (for example, through pipe  112  and air tubing  116 ) to another manifold assembly  912 . Alternatively, manifold assemblies which include an end cap end the streams of air and water and ensure that the plumbing system is sealed. 
     In  FIGS. 48-51 , the manifold assembly includes either two or three manifolds  1000 . More generally, however, manifold assembly  910  may include any suitable number of manifolds  1000  depending on the application and characteristics of the hot tub and the plumbing system. In general, the number of manifolds in a manifold assembly may correspond to the number of jets adjacent the manifold assembly. For example, a manifold assembly which is adjacent four jets may include two manifolds (having a total of four sets of egress ports) while a manifold assembly which is adjacent 16 jets may include 8 manifolds. 
     In some examples, hot tub  100  may include an odd number of jets and one of the manifolds in hot tub  100  may include an unused set of egress ports which may be plugged using the air and water plugs attached to the end cap. For example, a plumbing system which includes 29 jets may include 15 manifolds (having a total of 30 sets of egress ports), 14 of which couple to two lengths of tubing  120  and one of which couples to one length of tubing  120 . The manifold coupling to only one length of tubing  120  has an unused set of egress ports which may be plugged by air and water plugs which may be removed from end cap  1300 . 
     In use, streams of water and air may be passed to male adapter  1100  from a length of water pipe (such as pipe  112 ) and a length of air tubing (such as air tubing  116 ) respectively. Male adapter  1100  may pass the streams of water and air to manifold  1000 . Manifold  1000  may pass part of the streams of water and air to a length of tubing (such as tubing  120 ) through a set of egress ports and part of the streams of water and air to another component. In some examples, manifold  1000  may pass part of the streams of water and air to another manifold  920 . 
     In some examples, a plurality of manifolds  1000  may be coupled together; the manifold of the plurality of manifolds that is farthest downstream may be coupled to either a female adapter or an end cap. In cases where there is another manifold assembly further downstream, the plurality of manifolds may be coupled to a female adapter  1200 . Female adapter  1200  may be coupled to another length of pipe (such as pipe  112 ) and a length of air tubing (such as air tubing  116 ) and pass the streams of water and air to the pipe and air tubing respectively. In cases where there is not another manifold assembly downstream, the plurality of manifolds may be coupled to an end cap  1300 . End cap  1300  may ensure that the plumbing system is sealed. For example, in a system including three manifold assemblies  912 , the two upstream manifold assemblies may include female adapters  1200  while the most downstream manifold assembly may include end cap  1300 . 
     During installation, manifold assembly may be assembled in multiple steps or at multiple stations. A first step or steps may include coupling at least one male adapter  1100  to suitable lengths of pipe  112  and air tubing  116 . Coupling male adapter  1100  to pipe  112  and air tubing  116  may include any suitable process and/or structure. In some examples, coupling male adapter  1100  to pipe  112  and air tubing  116  may include using a glue, primer, and/or any suitable adhesive. For example, glue may be applied to the end of a length of pipe  112  and/or the inside of the upstream portion of the water conduit of male adapter  1100  before inserting the end of pipe  112  into the upstream portion of the water conduit of male adapter  1100 . 
     In some examples, pipe  112  may fit over the upstream portion of the water conduit of male adapter  1100  and glue may be applied to the inside of the end of pipe  112  and/or the outside of the water conduit of male adapter  1100 . In some examples, glue may not be used and friction and/or any suitable mechanical mechanism may be used to couple pipe  112  to male adapter  1100 . Similarly, in some examples, primer (and/or glue) may be applied to the end of a length of air tubing  116  and/or the inside of the upstream portion of the air conduit of male adapter  1100  before inserting the end of air tubing  116  into the upstream portion of the air conduit of male adapter  1100 . In some examples, air tubing  116  may fit over the upstream portion of the air conduit of the male adapter  1100  and primer may be applied to the inside of the end of air tubing  116  and/or the outside of the air conduit of male adapter  1100 . In some examples, primer may not be used and friction, vacuum pressure, and/or any suitable mechanical mechanism may be used to couple air tubing  116  to male adapter  1100 . 
     Another step or steps may include coupling female adapter  1200  to suitable lengths of pipe  112  and air tubing  116 . Coupling female adapter  1200  to pipe  112  and air tubing  116  may include any suitable process and/or structure. In some examples, coupling female adapter  1200  to pipe  112  and air tubing  116  may include using a glue, primer, and/or any suitable adhesive. For example, glue may be applied to the end of a length of pipe  112  and/or the inside of the downstream portion of the water conduit of female adapter  1200  before inserting the end of pipe  112  into the downstream portion of the water conduit of female adapter  1200 . In some examples, pipe  112  may fit over the downstream portion of the water conduit of female adapter  1200  and glue may be applied to the inside of the end of pipe  112  and/or the outside of the water conduit of female adapter  1200 . 
     In some examples, glue may not be used and friction and/or any suitable mechanical mechanism may be used to couple pipe  112  to female adapter  1200 . Similarly, in some examples, primer (and/or glue) may be applied to the end of a length of air tubing  116  and/or the inside of the downstream portion of the air conduit of female adapter  1200  before inserting the end of air tubing  116  inside of the downstream portion of the air conduit of female adapter  1200 . In some examples, air tubing  116  may fit over the downstream portion of the air conduit of the female adapter  1200  and primer may be applied to the inside of the end of air tubing  116  and/or the outside of the air conduit of female adapter  1200 . In some examples, primer may not be used and friction, vacuum pressure, and/or any suitable mechanical mechanism may be used to couple air tubing  116  to female adapter  1200 . 
     Assembling manifold assembly  912  may further include coupling each manifold  1000  with tubing  120 . Coupling manifold  1000  with tubing  120  may include any suitable process and/or structure. For example, tubing  120  may be slid over the ends of the air and water egress ports and a clamp (described in more detail below) may be used to prevent the tubing from sliding off. In some examples, a lubricant (e.g., soapy water) may be used to facilitate sliding the tubing over the air and water egress ports. In some examples, a lip formed on water egress port (such as lip  1020 ) may be configured to help keep tubing  120  on water egress port  1016  and/or may be configured to facilitate a water-tight connection. In some examples, tubing  120  may include dual extrusion tubing. In some examples, tubing  120  may include separate air and water tubes which may be installed one at a time on the air and water egress ports respectively. 
     Another step in the installation of manifold assembly  912  includes coupling together one or more manifolds  1000  (each of which are attached to tubing  120 ) and coupling the group of one or more manifolds  1000  to a male adapter  1100 . Manifolds  1000  may be coupled together by a “press-and-click” method (described above). For example, two manifolds may be aligned and then compressed together to overcome the resistive force of spring-biased clips (such as post clips  1032  and/or ridge clips  1040 ). In the embodiment shown in  FIGS. 32-51 , post clips  1032  and ridge clips  1040  are configured to facilitate coupling with the other manifold by engaging with features on the other manifold. 
     Any suitable number of manifolds  1000  may be coupled together to form a manifold cluster depending on the characteristics of hot tub  100 , the number of jets, and the characteristics of manifold assembly  912 . The manifold cluster may be coupled to male adapter  1100  by a “press-and-click” method (described above). For example, the male adapter be aligned with the most upstream manifold and then the adapter and the manifold cluster may be compressed together to overcome the resistive force of spring-biased clips (such as post clips  1032  and/or ridge clips  1040  of the most upstream manifold). In the embodiment shown in  FIGS. 32-51 , post clips  1032  and ridge clips  1040  on the upstream manifold are configured to facilitate coupling with the male adapter by engaging with retaining features on the adapter. 
     A further step in the installation of a manifold assembly  912  may include coupling a most downstream manifold of the manifold cluster to either female adapter  1200  or end cap  1300  depending on the characteristics of hot tub  100  and manifold assembly  912 . In examples where there is another manifold assembly farther downstream, the downstream manifold may be coupled to female adapter  1200 . The manifold cluster may be coupled to female adapter  1200  by a “press-and-click” method (described above). For example, the female adapter be aligned with the most downstream manifold and then the adapter and the manifold cluster may be compressed together to overcome the resistive force of spring-biased clips (such as post clips  1032  and/or ridge clips  1040  of the most downstream manifold). In the embodiment shown in  FIGS. 32-51 , post clips  1032  and ridge clips  1040  on the downstream manifold are configured to facilitate coupling with the female adapter by engaging with retaining features on the adapter. 
     In examples where manifold assembly  912  is the furthest downstream manifold assembly, the downstream manifold may be couple to end cap  1300 . The manifold cluster may be coupled to end cap  1300  by a “press-and-click” method (described above). For example, the end cap may be aligned with the most downstream manifold and then the end cap and the manifold cluster may be compressed together to overcome the resistive force of spring-biased clips (such as post clips  1328  and/or ridge clips  1334  on the end cap). In the embodiment shown in  FIGS. 32-51 , post clips  1328  and ridge clips  1334  on the end cap are configured to facilitate coupling with the manifold by engaging with retaining features on the manifold. 
     In some examples, each of the components of the first set of manifold assembly components may be configured to be able to be unlocked and/or uncoupled. Uncoupling the components may be accomplished by moving spring biased clips away from a default position and sliding the components apart. In some examples, a worker may accomplish this using a finger to move the spring biased clips and/or using a tool. Releasably coupling the components together may be advantageous as it may, among other advantages, allow a worker to uncouple components that were coupled to the wrong component by mistake. 
     As discussed, each of the components of the first set of manifold assembly components (e.g., manifold  1000 , male adapter  1100 , female adapter  1200 , and end cap  1300 ) may be constructed out of any suitable material. For example, the components of the first set of manifold assembly components may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). The components of the first set of manifold assembly components may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     Second Illustrative Manifold Assembly 
       FIGS. 52 and 53  depict the components of a second embodiment of a set of manifold assembly components. The second embodiment of the set of manifold assembly components includes a second embodiment  1400  of manifold  920 , a second embodiment  1500  of male manifold adapter  930 , and a second embodiment  1600  of manifold end cap  950 . Together, male manifold adapter  1500 , one or more manifold  1400 , and manifold end cap  1600  may form an illustrative manifold assembly  914 . Additionally, or alternatively, male manifold adapter  1500  may be referred to as a male adapter; and/or manifold end cap  1300  may be referred to as an end cap. 
     Each of the components in the second embodiment of the set of manifold assembly components may be substantially similar to the corresponding component in the first set of manifold assembly components. Accordingly, only an abbreviated discussion will be provided below of features which are substantially similar to the first embodiment. A few primary differences will be discussed below, however, there may be various differences in the shape, dimensions, and/or style of the components compared with the first set of manifold assembly components. 
     First, where the water conduits of manifold  1000  and male manifold adapter  1100  (i.e., water conduits  1002  and  1102  respectively) each included two recesses for O-rings and two O-rings (i.e., recesses  1048  and  1134  respectively and O-rings  1050  and  1134  respectively), a water conduit  1402  of manifold  1400  and a water conduit  1502  of male manifold  1500  each include one recess and one O-ring. Also, in place of post clips and retaining posts as in the first set of manifold assembly components (such as post clips  1032  and  1328  on manifold  1000  and end cap  1300  and retaining post  1038  and  1130  on manifold  1000  and male adapter  1100 ), the water conduits of each of the components in the second set of manifold assembly components each include a retaining ridge and/or a plurality of ridge clips. Further, where water cap  1322  and air cap  1326  of end cap  1300  are curved, end cap  1600  includes a water cap  1622  and an air cap  1626  which are flat. Each of these components will be discussed in further detail below. 
     For example, water conduit  1402  of manifold  1400  defines a first longitudinal axis  1404  and includes an upstream end  1424  and a downstream end  1426 . Unlike manifold  1000  which includes two recesses  1048  (each of which holds an O-ring  1050 ), downstream end  1426  of water conduit  1402  of manifold  1400  includes one recess  1440  configured to hold an O-ring  1442 . Recess  1440  and O-ring  1442  are substantially similar to recesses  1048  and O-rings  1050  respectively. Downstream end  1426  of water conduit  1402  further includes a retaining ridge  1448  configured to couple with ridge clips on the water conduit of another component. 
     Retaining ridge  1448  may include any suitable structure configured to engage with spring-biased clips (e.g., ridge clips) on the upstream end of the water conduit of another component. For example, retaining ridge  1448  may include a ridge which extends around substantially the entire perimeter of the water conduit. Upstream end  1424  of water conduit  1402  further includes a plurality of spring-biased clips or ridge clips  1450  configured to couple with a retaining ridge. Ridge clips  1450  may include any suitable structure configured to couple with a retaining ridge disposed on the water conduit of another component. Ridge clips  1450  include a flexible support  1452  and a sloped lip  1454  which is configured to engage with the retaining ridge of another component. 
     Manifold  1400  further includes two air conduits  1406 , each of which define a second longitudinal axis  1408 . Air conduits  1406  are substantially identical to air conduits  1006 . A periphery of air conduit  1406  is joined to a periphery of water conduit  1402  by a support structure. The support structure is substantially identical to support structure  1014  of manifold  1000 . An upstream end  1428  of air conduit  1406  includes at least one ridge clip  1432  configured to couple with a retaining ridge on the air conduit of another component. Ridge clip  1432  includes a flexible support  1434  and a sloped lip  1436  and may be substantially similar to ridge clips  1040 . 
     A downstream end  1430  of air conduit  1406  includes a retaining ridge  1438  configured to couple with retaining clips on another component. Downstream end  1430  of air conduit  1406  further includes a recess configured to hold an O-ring. The recess on air conduit  1406  is substantially similar to recess  1052  and the O-ring on air conduit  1406  may be substantially similar to O-ring  1054 . Manifold  1400  further includes a set of egress ports  1422 . Set of egress ports  1422  includes a water egress port  1416  and an air egress port  1418 , which may be substantially similar to water egress port  1016  and air egress port  1018  respectively. Water egress port  1416  includes a lip or ridge  1420 . 
     Similarly, water conduit  1502  of male adapter  1500  defines a first longitudinal axis  1504  and includes an upstream end  1516  and a downstream end  1518 . Unlike male adapter  1100  which includes two recesses  1134  (each holding an O-ring  1136 ), downstream end  1518  of water conduit  1502  of male adapter  1500  includes one recess  1526  configured to hold an O-ring  1528 . Recess  1526  and O-ring  1528  are substantially similar to recess  1134  and O-ring  1136  respectively. Downstream end  1518  further includes a retaining ridge  1534  configured to couple with ridge clips on another component. Retaining ridge  1534  may include any suitable structure configured to engage with spring-biased clips (e.g., ridge clips) on the upstream end of the water conduit of another component. 
     For example, retaining ridge  1534  may include a ridge which extends around substantially the entire perimeter of the water conduit. Male adapter  1500  further includes two air conduits  1506 , each of which define a second longitudinal axis  1508 . Air conduits  1506  are substantially identical to air conduits  1106 . A periphery of air conduit  1506  is joined to a periphery of water conduit  1502  by a support structure  1514 . Support structure  1514  is substantially identical to support structure  1114  of male adapter  1100 . A downstream end  1522  of air conduit  1506  includes a retaining ridge  1524  configured to couple with retaining clips on another component. Downstream end  1522  of air conduit  1506  further includes a recess configured to hold an O-ring. 
     The recess on air conduit  1506  is substantially similar to recess  1138  and the O-ring on air conduit  1506  may be substantially similar to O-ring  1140 . Further, upstream end  1516  of water conduit  1502  is configured to couple with a length of pipe, such as pipe  112 . An upstream end  1520  of air conduit  1506  is configured to couple with a length of air tubing, such as air tubing  116 . Upstream end  1516  and upstream end  1520  may be substantially similar to upstream end  1116  and upstream end  1120  and may couple to pipe  112  and air tubing  116  respectively in substantially the same way as upstream end  1116  and upstream end  1120 . 
     Also, water closure  1602  of end cap  1600  defines a first longitudinal axis  1604  and includes an upstream end  1616  and a downstream end  1620 . End cap  1600  further includes two air closures  1606 , each of which define a second longitudinal axis  1608 . Air closures  1606  are substantially identical to air closures  1606 . A periphery of air closure  1606  is joined to a periphery of water closure  1602  by a support structure. The support structure is substantially identical to support structure  1314  of end cap  1300 . Unlike end cap  1300  which includes water and air caps which are convex, downstream end  1620  of water closure  1602  of end cap  1600  includes a flat water cap  1622 . Similarly, a downstream end  1624  of an air closure  1606  includes a flat air cap  1626 . Upstream end  1616  of water closure  1602  further includes a plurality of spring-biased clips or ridge clips  1634  configured to couple with a retaining ridge on another component. 
     Ridge clips  1634  may include any suitable structure configured to couple with a retaining ridge disposed on the water conduit of another component. Ridge clips  1634  include a flexible support  1636  and a sloped lip  1638  which is configured to engage with the retaining ridge of another component. An upstream end  1618  of air closure  1606  includes at least one ridge clip  1628  configured to couple with a retaining ridge on the air conduit of another component. Ridge clip  1628  includes a flexible support  1630  and a sloped lip  1632  and may be substantially similar to ridge clips  1334 . 
     While  FIGS. 52 and 53  do not show a female manifold adapter, in some examples, the second set of manifold assembly components may include a second embodiment of a female manifold adapter. The second embodiment of a female manifold adapter may be substantially the same as female adapter  1200  except that it may include ridge clips on the water conduit in place of post clips  1228 . The ridge clips may be configured to couple with a retaining ridge disposed on the water conduit of another component. 
     Each of the components in the second set of manifold assembly components may be constructed out of any suitable material. For example, manifold  1400 , male adapter  1500 , end cap  1600 , and/or the second embodiment of a female manifold adapter may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). Each of the components in the second set of components may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     C. Illustrative Plumbing System 
     As shown in  FIGS. 54-59 , this section describes an illustrative plumbing system suitable for use in a hot tub, swim spa or the like. The hot tub plumbing system may include any suitable structures and/or mechanisms configured to simultaneously deliver separate streams of air and water to a plurality of jets. For example, the plumbing system may include a plurality of manifold assemblies, a plurality of lengths of tubing, and/or a plurality of jet assemblies. In the block diagram shown in  FIG. 54 , a plumbing system  1700  includes water supply  106 , water pipe  112 , air supply  114 , air tubing  116 , at least one manifold assembly  910 , tubing  1710 , and at least one jet assembly  200 . In some examples, any of the components described in the previous sections may be used in plumbing system  1700 . 
     Overview 
     In general, hot tub plumbing system  1700  may comprise: a manifold (such as manifolds  118 ,  920 ,  1000 , and/or  1400  described previously) configured to receive separate air and water supply streams and to direct those streams into a water egress port (such as water egress ports  1016  and/or  1416 ) and an air egress port (such as air egress port  1018  and/or  1418 ), respectively, wherein the water egress port and the air egress port are substantially parallel and adjacent to each other; a flexible dual extrusion tube (such as tubing  1710 ) including a first hollow cylindrical portion configured to couple to the water egress port and a second hollow cylindrical portion configured to couple to the air egress port, wherein the first and second hollow cylindrical portions are joined together at peripheral portions; a jet back (such as straight jet backs  122 ,  302 ,  402 , and  502 , and/or angled jet backs  602 ,  702 , and  802 ) including a pair of adjacent parallel hollow protrusions each configured to receive one of the streams of air and water from a respective one of the hollow cylindrical portions of the dual extrusion tube; and a jet body (such as jet bodies  124  and/or  304 ,  404 ,  504 ,  604 ,  704 , and/or  804 ) configured to receive the streams of air and water from the jet back, to merge the streams of air and water together to form a mixed stream of air and water, and to provide the mixed stream of air and water from an outlet and thereby into the interior of the hot tub. 
     In some examples, the jet back may further include a central portion (such as central portion  316  in jet assembly  300 ) configured to create a water tight seal with the jet body, and an attachment mechanism extending from a first end of the central portion and configured to attach the jet back to the jet body in a secure manner. In some examples, the attachment mechanism may include a pair of opposed, spring-biased clips (such as spring-biased clips  328  in jet assembly  300 ) extending from the first end of the central portion of the jet back, each opposed clip configured to snap into spring-biased engagement with a complementary retaining ridge (such as ridge  530  on jet assembly  500 ) or groove (such as  330  on jet assembly  300 ) disposed at a periphery of the jet body. In some examples, the jet body further includes at least one O-ring (such as O-rings  338  on jet assembly  300 ) disposed around a periphery of the jet body, and an inner cylindrical surface of the central portion of the jet back is configured to fit around the O-ring in a substantially water tight compression fit. 
     In some examples, hot tub plumbing system  1700  further comprises a jet insert (such as jet inserts  126 ,  506 , and/or  806 ) configured fit within an aperture of a hot tub body, to receive the mixed stream of air and water from the jet body outlet, and to channel the mixed stream of air and water into an interior portion of the hot tub body through the aperture. In some examples, hot tub plumbing system  1700  further comprises a one-piece clamp (described below) configured to hold the dual extrusion tube in water tight engagement with the egress ports of the manifold. In some examples, the clamp is also configured to hold the dual extrusion tube in water tight engagement with the protrusions of the jet back. For example, the clamp may define a pair of contiguous arcuate apertures and a selectively releasable end portion having first and second sets of complementary ratcheting teeth configured to be engaged with each other upon compression of the end portion. 
     In other words, hot tub plumbing system  1700  may comprise a manifold configured to receive separate air and water supply streams and to channel the streams into a water egress port and an air egress port; a flexible dual extrusion tube including a first tubular portion configured to couple to the water egress port and a second tubular portion configured to couple to the air egress port, wherein the first and second tubular portions are joined together in a figure-eight configuration; and a jet back including a pair of adjacent parallel hollow protrusions each configured to receive one of the streams of air and water from a respective one of the tubular portions of the dual extrusion tube. Hot tub plumbing system  1700  may further comprise a jet body configured to receive the streams of air and water from the jet back, to merge the streams of air and water together to form a mixed stream of air and water, and to channel the mixed stream of air and water into an outlet. In some examples, hot tub plumbing system  1700  may further comprise a jet insert configured to be attached within an aperture of a hot tub shell, to receive the mixed stream of air and water from the outlet of the jet body, and to channel the mixed stream of air and water into the hot tub through the aperture. 
     Hot tub plumbing system  1700  may include separate water and air systems. For example, water supply  106 , pipe  112 , the water conduits of the components of manifold assembly  910 , the water portion of tubing  1710 , and the water ingress port of jet assembly  200  may form a water system. In some examples, the water system may be under any suitable pressure. For example, the water system may be under approximately 25 pounds per square inch (psi) of pressure. In some examples, the water system may be under approximately 5 psi, 10 psi, 15 psi, 30 psi, and/or any other suitable amount of pressure. The amount of pressure applied to the water system may be configured to facilitate the flow of water through the water system. Water may be supplied to the water system by water supply  106  which may include a pump, filter, and/or any other suitable source of water. In some examples, water may be recycled by the hot tub such that water from the hot tub body is removed, filtered, and reintroduced into the water system. 
     Air supply  114 , tubing  116 , the air conduits of the components of manifold assembly  910 , the air portion of tubing  1710 , and the air ingress port of jet assembly  200  may form an air system. In some examples, the air system may be under any suitable pressure, and in some cases the air system may be under vacuum pressure rather than positive pressure. For example, the air system may be under less than approximately 20 inches of mercury (in.-Hg) of vacuum pressure. The amount of vacuum applied to the air system may be configured to facilitate the flow of air through the system. 
     In some examples, the vacuum pressure applied to the air system may be produced by the flow of water through the nozzles in the jet assemblies. In other words, water flowing past the air ingress ports of the jet assembly may draw air into the jet (and thus through the air system) due to the Venturi effect. Air may be supplied to the air system by air supply  114 , which may include a pump and/or an air vent open to the atmosphere. In some examples, the air system may use atmospheric air and/or filtered air. In some examples, atmospheric air may enter the air system through an air vent. In some examples, the air vent may be adjustable by a user to manipulate the ratio of air and water that the jet assemblies introduce into the hot tub body. 
     Any suitable dimensions may be used for each component. Components which couple together may have complementary dimensions. For example, the outer diameters of the air and water ingress and egress ports may be approximately the same as the inner diameter of the dual extrusion tubing used in the system. 
     First Embodiment of a Hot Tub Plumbing System 
       FIG. 55  depicts a portion of a first embodiment  1702  of plumbing system  1700  including an example of manifold assembly  912  and four jet assemblies  300 .  FIG. 56  depicts another portion of first embodiment  1702  of plumbing system  1700  including another example of manifold assembly  912  and four jet assemblies. 
     As shown in  FIG. 55 , system  1702  includes water pipe  112  and air tubing  116  which couple with an example of manifold assembly  912 . This example of manifold assembly  912  includes male manifold adapter  1100 , two manifolds  1000 , and manifold end cap  1300 . Each of the components of manifold assembly  912  are described in more detail above. Male manifold adapter  1100  couples with pipe  112  and air tubing  116 . 
     As shown in  FIG. 56 , another portion of system  1702  includes water pipe  112  and air tubing  116  which couple with another example of manifold assembly  912 . This example of manifold assembly  912  includes male manifold adapter  1100 , two manifolds  1000 , and female manifold adapter  1200 . Each of the components of manifold assembly  912  are described in more detail above. Male manifold adapter  1100  couples with pipe  112  and air tubing  116  and female manifold adapter  1200  couples with a second length of each of water pipe  112  and air tubing  116 . 
     Each manifold  1000  in both examples of manifold assembly  912  couples with two lengths of tubing  1712 , each of which couples with an example of jet assembly  300 . Tubing  1712  is dual extrusion tubing and an example of tubing  1710 , which will be described in more detail below. As described above, each jet assembly  300  may include a jet back  302 , a nozzle  308 , and/or a jet body  304 . In some examples, each jet assembly  300  also may include a jet insert. 
     Both portions of system  1702  (shown respectively in  FIG. 55  and  FIG. 56 ) include a plurality of clamps  1800  which are configured to facilitate a water- and/or air-tight seal between tubing  1712  and manifold  1000  and/or jet back  302 . Clamps  1800  are positioned over the ends of tubing  1712  where tubing  1712  fits over set of egress ports  1022  on manifold  1000  and where tubing  1712  fits over water ingress port  310  and air ingress port  312  on jet back  302 . Clamp  1800  will be described in more detail below with respect to  FIGS. 57, 58, and 59 . 
     In some examples, the portion of system  1702  shown in  FIG. 56  may be positioned upstream of the portion of system  1702  shown in  FIG. 55 . In some examples, system  1702  may include any suitable number of manifold assemblies  912  and may include any suitable configurations of manifold assembly  912 . For example, each manifold assembly may include any suitable number of manifolds and any suitable adapters and/or end caps. System  1702  may further include a water source (for example, water supply  106 ) and an air source (for example, air supply  114 ). In some examples, system  1702  may further include any suitable components and/or structures. For example, system  1702  may include any suitable kinds of tubing, valves, filters, tube splitters, and/or other fittings. 
     Pipe  112  may include any suitable pipe configured to carry water to manifold assembly  912 . For example, pipe  112  may include approximately 2 inch pipe. In some examples, pipe  112  may be constructed out of industrial grade, clear, flexible PVC and/or any other suitable material. Air tubing  116  may include any suitable pipe and/or tubing configured to carry air to manifold assembly  912 . For example, air tubing  116  may include approximately 0.5 inch pipe. In some examples, air tubing  116  may be constructed out of industrial grade, clear, flexible PVC and/or any other suitable material. 
     Many of the components of system  1702  are described in more detail above and may include any suitable dimensions and/or materials such as those described above. For example, each of the components may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). Further, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     First Embodiment of a One-Piece Clamp 
       FIG. 57  is an isometric view of a first embodiment  1800  of a one-piece clamp suitable for use with dual extrusion tubing.  FIG. 58  is a top plan view of one-piece clamp  1800  of  FIG. 57 .  FIG. 59  depicts the clamp of  FIGS. 57-58  in use with a jet assembly and dual extrusion tubing; clamp  1800  is shown twice, once in an open position  1802  and once in closed position  1804 . 
     Clamp  1800  may include any suitable structure configured to hold dual extrusion tubing  1712  in water- and/or air-tight engagement with the egress ports of manifold  1000  and/or the ingress ports of jet back  302 . For example, clamp  1800  includes a single piece which includes a pair of contiguous arcuate apertures  1810 ,  1812 . A first arcuate aperture  1810  may be configured to fit around a water passage of tubing  1712  and a second arcuate aperture  1812  may be configured to fit around an air passage of tubing  1712 . Clamp  1800  may further include an end portion  1814  having a first set of ratcheting teeth  1816  and a second set of ratcheting teeth  1818 . In the example shown in  FIGS. 57-59 , end portion  1814  is adjacent second arcuate aperture  1812 ; in some examples, end portion  1814  may be adjacent first arcuate aperture  1810  and/or any other suitable portion of clamp  1800 . 
     First set of ratcheting teeth  1816  and second set of ratcheting teeth  1818  may be complementary and may be configured to be engaged with each other upon compression of end portion  1814 . For example, in  FIGS. 57-59 , first set of ratcheting teeth  1816  is disposed on a lower surface of a first upper arm  1820 . First upper arm  1820  and a first lower arm  1822  form a first slot  1824 . Similarly, second set of ratcheting teeth  1818  is disposed on an upper surface of a second lower arm  1826 . Second lower arm  1826  and a second upper arm  1828  form a second slot  1830 . When clamp  1800  is closed (as shown in  FIG. 59 ), first upper arm  1820  fits within second slot  1830  and second lower arm  1828  fits within first slot  1824 . Thus, the first and second sets of ratcheting teeth are in contact and engage. 
     The teeth of the first and second sets of ratcheting teeth may be sloped as best seen in  FIG. 58 , such that forward edges of each set of teeth can pass over each other when end portion  1814  is compressed. Once one or more of the teeth have passed over each other, they may engage or hook together so as to prevent the clamp from opening. For example, a tooth may fit in a space between adjacent teeth on the opposite set of ratcheting teeth. 
     In some examples, clamp  1800  may be releasable; among other advantages, this may allow a user to uncouple a length of tubing and a set of ports that have been connected by mistake, or for the purpose of replacing damaged or worn tubing, manifold components and/or jet assembly components. For example, a user may be able to compress end portion  1814  to disengage the two sets of ratcheting teeth, shift the arms such that the two sets of ratcheting may pass by each other without engaging, and release end portion  1814  such that it opens. In some examples, the two sets of ratcheting teeth may be resiliently flexible such that the teeth flex away from each other when end portion  1814  is compressed, allowing the two sets of ratcheting teeth to pass by each other. In some examples, the two sets of ratcheting teeth may be releasable by pulling the clamp open with a force greater than some threshold force, such that the two sets of ratcheting teeth flex past each other to disengage. In some examples, any suitable engagement mechanism and/or structure may be used to hold clamp  1800  closed when compressed. For example, clamp  1800  may include spring biased clips, hooks, ridges, magnets, and/or any suitable structure. 
     Clamp  1800  may have any suitable dimensions configured to facilitate holding dual extrusion tubing  1712  in water- and/or air-tight engagement with the egress ports of manifold  1000  and/or the ingress ports of jet back  302 . For example, first arcuate aperture  1810  may have an inner radius between approximately 0.25 inches and approximately 1.0 inches when in closed position  1804 . In some examples, first arcuate aperture  1810  may have an inner radius of approximately 0.500 inches when in closed position  1804 . First arcuate aperture  1810  may have any suitable wall thickness. For example, first arcuate aperture  1810  may have a wall thickness between approximately 0.05 inches and 0.25 inches. In some examples, first arcuate aperture  1810  may have a wall thickness of approximately 0.125 inches. Furthermore, second arcuate aperture  1812  may have an inner radius between approximately 0.25 inches and approximately 1.0 inches when in closed position  1804 . In some examples, second arcuate aperture  1812  may have an inner radius of approximately 0.315 inches when in closed position  1804 . Clamp  1800  may have any suitable thickness. For example, clamp  1800  may have a thickness between approximately 0.1 inches and approximately 1.0 inches. In some examples, clamp  1800  may have a thickness of approximately 0.276 inches. 
     Clamp  1800  may be constructed out of any suitable material. For example, clamp  1800  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), nylon, and/or any other suitable materials having similar properties (i.e., stiffness etc.). Clamp  1800  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, clamp  1800  may be constructed out of molded nylon. 
     Second Embodiment of a Hot Tub Plumbing System 
       FIG. 60  depicts a partially exploded view of a portion of a second embodiment  1704  of plumbing system  1700 , including an embodiment of a manifold assembly having four manifolds  920  and four jet assemblies  500 .  FIG. 61  depicts a partially exploded view of a magnified portion of second embodiment  1704  of plumbing system  1700  including a single manifold  920  and a single jet assembly  500 . 
     As shown in  FIG. 60 , a portion of system  1704  includes valve  108  and water pipe  112  which couples with an embodiment of a manifold assembly. In some examples, system  1704  may include air tubing (such as air tubing  116 ) which may couple to the manifold assembly. This example includes a male manifold adapter  930 , four manifolds  920 , and a manifold end cap  950 . Each of the components of the manifold assembly are described in more detail above; the embodiments shown in  FIG. 60  may be generally similar to second embodiment  914  of manifold assembly  910 . 
     Each manifold  920  in system  1704  couples with at least one length of tubing  1714 , which couples with an exemplary jet assembly  500 . Tubing  1714  is dual extrusion tubing, and is an example of tubing  1710  which will be described in more detail below. As described above, each jet assembly  400  may include a jet back  502 , a jet body  504 , and/or a jet insert  506 . 
     While not shown in  FIGS. 60 and 61 , in some examples, system  1704  may include a plurality of clamps, such as clamps  1800  depicted in  FIGS. 55-59 , or clamps  1900  depicted in  FIGS. 62-63  and described in more detail below, which are configured to facilitate a water- and/or air-tight seal between tubing  1714  and manifold  920  and/or jet back  502 . For example, the clamps may be positioned over the ends of tubing  1714  where tubing  1714  fits over the egress ports on manifold  920  and where tubing  1714  fits over the ingress ports on jet back  502 . 
     System  1704  may include any suitable number of manifold assemblies, and each manifold assembly may include any suitable number of manifolds  920 . System  1704  may further include a water source (for example, water supply  106 ) and an air source (for example, air supply  114 ). In some examples, system  1704  may further include any suitable components and/or structures. For example, system  1704  may include any suitable kinds of tubing, valves filters, tube splitters, and/or other fittings. 
     Many of the components of system  1704  are described in more detail above and may include any suitable dimensions and/or materials such as those described above. For example, each of the components may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). Further, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     Second Embodiment of a One-Piece Clamp 
       FIG. 62  is an isometric view of a second embodiment  1900  of a one-piece clamp suitable for use with dual extrusion tubing.  FIG. 63  is a top plan view of one-piece clamp  1900  of  FIG. 62 . 
     Clamp  1900  may include any suitable structure configured to hold dual extrusion tubing  1714  in water- and/or air-tight engagement with the egress ports of manifold  920  and/or the ingress ports of jet back  502 . For example, clamp  1900  includes a single piece which includes a pair of contiguous arcuate apertures. A first arcuate aperture  1910  may be configured to fit around a water passage of tubing  1714  and a second arcuate aperture  1912  may be configured to fit around an air passage of tubing  1714 . Clamp  1900  may further include an end portion  1914  having a first set of ratcheting teeth  1916  and a second set of ratcheting teeth  1918 . In the example shown in  FIGS. 62-63 , end portion  1914  is adjacent second arcuate aperture  1912 ; in some examples, end portion  1914  may be adjacent first arcuate aperture  1910  and/or any other suitable portion of clamp  1900 . 
     First set of ratcheting teeth  1916  and second set of ratcheting teeth  1918  may be complementary and may be configured to be engaged with each other upon compression of end portion  1914 . For example, in  FIGS. 62-63 , first set of ratcheting teeth  1916  is disposed on a lower surface of a first upper arm  1920 . First upper arm  1920  and a first lower arm  1922  form a first slot  1924 . Similarly, second set of ratcheting teeth  1918  is disposed on an upper surface of a second lower arm  1926 . Second lower arm  1926  and a second upper arm  1928  form a second slot  1930 . When clamp  1900  is closed, first upper arm  1920  fits within second slot  1930  and second lower arm  1928  fits within first slot  1924 . The teeth of the first and second sets of ratcheting teeth may be sloped such that forward edges of each set of teeth can pass over each other when end portion  1914  is compressed. Once one or more of the teeth have passed over each other, they may engage so as to prevent the clamp from opening. For example, a tooth may fit in a space between adjacent teeth on the opposite set of ratcheting teeth. 
     In some examples, clamp  1900  may be releasable; among other advantages, this may be advantageous as it may allow a user to uncouple a length of tubing and a set of ports that have been connected by mistake, or to replace defective, broken or worn parts. For example, a user may be able to compress end portion  1914  to disengage the two sets of ratcheting teeth, shift the arms such that the two sets of ratcheting may pass by each other without engaging, and release end portion  1914  such that it opens. In some examples, the two sets of ratcheting teeth may be resiliently flexible such that the teeth flex away from each other when end portion  1914  is compressed, allowing the two sets of ratcheting teeth to pass by each other. In some examples, the two sets of ratcheting teeth may be releasable by pulling the clamp open with sufficient force, such that the two sets of ratcheting teeth flex past each other to disengage. In some examples, any suitable engagement mechanism and/or structure may be used to hold clamp  1900  closed when compressed. For example, clamp  1900  may include spring biased clips, hooks, ridges, magnets, and/or any suitable structure. 
     Clamp  1900  may have any suitable dimensions configured to facilitate holding dual extrusion tubing  1714  in water- and/or air-tight engagement with the egress ports of manifold  920  and/or the ingress ports of jet back  502 . For example, first arcuate aperture  1810  may have any suitable wall thickness and clamp  1800  may have any suitable thickness. 
     Clamp  1900  may be constructed out of any suitable material. For example, clamp  1900  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), nylon, and/or any other suitable materials having similar properties (i.e., stiffness etc.). Clamp  1900  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, clamp  1900  may be constructed out of molded nylon. 
     Illustrative Tubing 
       FIG. 64  includes a cross-section of an example of dual extrusion tubing  1710 . Tubing  1710  may include any suitable structure configured to convey streams of air and water from the egress ports of manifold  920  to the ingress ports of jet assembly  200 . In the example shown in  FIG. 64 , tubing  1710  is dual extrusion tubing. In some examples, tubing  1710  may include any suitable kind of tubing. For example, tubing  1710  may include separate air and water tubes. 
     In the embodiment shown in  FIG. 64 , tubing  1710  is flexible dual extrusion tubing including a first hollow cylindrical portion  1720  configured to couple to the water egress port and a second hollow cylindrical portion  1722  configured to couple with the air egress port. First portion  1720  and second portion  1722  are joined together at peripheral portions. For example, a periphery  1724  of first portion  1720  may be joined with a periphery  1726  of second portion  1722 . In other words, tubing  1710  is a flexible dual extrusion tube and includes a first tubular portion configured to couple to the water egress port and a second tubular portion configured to couple to the air egress port. The first and second tubular portions are joined together in a figure-eight configuration. 
     In some embodiments, first hollow cylindrical portion  1720  and second hollow cylindrical portion  1722  may be joined by any suitable mechanism. In some embodiments, first hollow cylindrical portion  1720  and second hollow cylindrical portion  1722  may not be joined. For example, first hollow cylindrical portion  1720  may include a water tube and second hollow cylindrical portion  1722  may include an air tube. In some examples, the water tube and the air tube may be coupled with the same manifolds and/or jet assemblies and/or may travel substantially similar paths. In some examples, the water tube and the air tube may be couple with different manifolds and/or jet assemblies and/or may travel substantially different paths. In some examples, the water tube and the air tube may or may not be substantially the same lengths. 
     Tubing  1710  may have any suitable dimensions configured to facilitate coupling with the egress ports of manifold  920  and the ingress ports of jet assembly  200 . For example, first portion  1720  may have an inner diameter between approximately 0.5 inches and approximately 1.0 inches. In some examples, first portion  1720  may have an inner diameter of approximately 0.750 inches. First portion  1720  may have any suitable wall thickness. For example, first portion  1720  may have a wall thickness between approximately 0.05 inches and 0.25 inches. In some examples, first portion  1720  may have a wall thickness of approximately 0.125 inches. 
     Second portion  1722  may have an inner diameter between approximately 0.25 inches and approximately 0.5 inches. In some examples, second portion  1722  may have an inner diameter of approximately 0.375 inches. Second portion  1722  may have any suitable wall thickness. For example, second portion  1722  may have a wall thickness between approximately 0.03 inches and approximately 0.1 inches. In some examples, second portion  1722  may have a wall thickness of approximately 0.080 inches. 
     Tubing  1710  may be constructed out of any suitable material. For example, tubing  1710  may include any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). Tubing  1710  may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, tubing  1710  may be constructed out of industrial grade, clear, flexible PVC on dual extruded tooling. 
     First embodiment  1702  of system  1700  and second embodiment  1704  of system  1700  each include an embodiment of tubing  1710  (tubing  1712  and tubing  1714  respectively). Each embodiment of tubing  1710  may include any suitable structure and/or dimensions suitable for coupling with other components of the system. For example, the inner diameters of first portion  1720  and second portion  1722  may correspond to outer diameters of the corresponding embodiment of the egress ports of manifold  920  and the ingress ports of jet assembly  200 . For example, the dimensions of tubing  1712  may correspond with the dimensions of the ports of manifold  1000  and jet assembly  300 . 
     D. Illustrative Methods of Assembly 
     This section describes steps of an illustrative method for installing a hot tub plumbing system; see  FIG. 65 . Aspects and/or components of hot tub  100 , jet assembly  200 , manifold assembly  910 , and/or system  1700  may be utilized in the method steps described below. Where appropriate, reference may be made to components and systems that may be used in carrying out each step. These references are for illustration and are not intended to limit the possible ways of carrying out any particular step of the method. 
     Although the methods described in this section are described with reference to a plumbing system for a hot tub and/or spa, the disclosed methods may be used for any plumbing system involving multiple pieces wherein efficient assembly is needed. 
       FIG. 65  is a flowchart illustrating steps performed in an illustrative method and may not recite the complete process or all steps of the method. Although various steps of method  2000  are described below and depicted in  FIG. 65 , the steps need not necessarily all be performed, and in some cases may be performed simultaneously or in a different order than the order shown. 
     At step  2002 , a worker inserts a jet body (such as jet body  124  and/or  204 ) into an aperture in a wall of the hot tub body (such as hot tub body  104 ). In some examples, step  2002  may include using a tool, threading the jet body into the hot tub body, and/or installing additional components such as gaskets (for example, compressive gaskets). In some examples, step  2002  may include and/or follow a step which includes creating the aperture in the hot tub body. At optional step  2004 , the worker couples a jet insert (such as jet insert  126  and/or  106 ) to the jet body. In some examples, coupling the jet insert to the jet body may facilitate securing the jet body to the hot tub body. In some examples, step  2004  may be combined with step  2002 , may occur later, may be combined with another method, and/or may not occur at all. 
     At step  2006 , the worker couples separate air and water supply lines (such as pipe  112  and air tubing  116 ) to a male adapter (such as adapter  110  or male adapter  930 ). In some examples, any suitable mechanism for coupling the supply lines to the adapter may be used. In some examples, this step may include the application of glue, primer, and/or any other suitable adhesive to the supply lines and/or the adapter. For example, glue may be applied to the outside of the end of the water supply line before it is inserted into the end of the water conduit of the male adapter. Similarly, primer may be applied to the outside of the end of the air supply line before it is inserted into the end of the air conduit of the male adapter. In some examples, this step may include the application of a clamp and/or any other suitable connection mechanism. 
     At step  2008 , the worker couples a first end of a length of tubing (such as tubing  1710 ) to a manifold (such as manifold  118  or  920 ). In some examples, coupling the tubing to the manifold includes coupling a first portion of the tubing (such as first portion  1720 ) to a water egress port (such as water egress port  1016 ) of the manifold and a second portion of the tubing (such as second portion  1722 ) to an air egress port (such as air egress port  1018 ) of the manifold. For example, the tubing may be dual extrusion tubing and the first and second portions may be joined at a periphery. In some examples, coupling the tubing to the egress ports may include sliding the tubing over the end of the egress ports. In some examples, step  2008  may include the use of a lubricant (such as soapy water) to facilitate sliding the end of the tubing over the end of the egress ports. 
     At step  2010 , the worker clamps the tubing to the manifold using a dual aperture clamp (such as clamp  1800  or  1900 ). The clamp ensures that the tubing does not slip off of the egress ports of the manifold; the clamp cannot flex around a lip on the water egress port (such as lip  1020  or  1420 ) and so cannot slip off of the set of egress ports. The clamp compresses the tubing against the egress ports and ensures a water- and/or air-tight seal between the tubing and the egress ports. For example, a water- and air-tight seal can be achieved using the clamp and without the use of glue, primer, and/or other adhesives. Additionally, the worker may place the clamp where the clamp is needed and tighten the clamp in place. In other words, in may not be necessary to put the clamp on the tubing before coupling the tubing to the ports and then move the clamp to get the correct positioning, instead the clamp can be placed in the correct location right away. 
     At step  2012 , the worker couples a second end of the length of tubing to the jet back. In some examples, coupling the tubing to the jet back includes coupling the first portion of the tubing to a water ingress port (such as water ingress port  310 ) of the jet back and the second portion of the tubing to an air ingress port (such as air ingress port  312 ) of the jet back. For example, the tubing may be dual extrusion tubing the first and second portions may be joined at a periphery. In some examples, coupling the tubing to the ingress ports may include sliding the tubing over the end of the ingress ports. In some examples, step  2012  may include the use of a lubricant (such as soapy water) to facilitate sliding the end of the tubing over the end of the ingress ports. 
     At step  2014 , the worker clamps the tubing to the jet back using another dual aperture clamp (such as clamp  1800  or  1900 ). The clamp ensures that the tubing does not slip off of the ingress ports of the jet back; the clamp cannot flex around a lip disposed on the water ingress port (such as lip  316  on jet assembly  300 ) and so cannot slip off of the set of ingress ports. The clamp compresses the tubing against the ingress ports and ensures a water- and/or air-tight seal between the tubing and the ingress ports. For example, a water- and air-tight seal can be achieved using the clamp and without the use of glue, primer, and/or other adhesives. Additionally, the worker may place the clamp where the clamp is needed and tighten the clamp in place. In other words, in may not be necessary to put the clamp on the tubing before coupling the tubing to the ports and then move the clamp to get the correct positioning, instead the clamp can be placed in the correct location right away. 
     At step  2016 , the worker couples the manifold to another manifold, an adapter, and/or an end cap. For example, the worker may assemble one or more manifold assemblies (such as manifold assembly  910 ). In some examples, the worker may couple the manifold to the male adapter and to a second manifold. In some examples, the worker may couple the manifold to a second and a third manifold. In some examples, the worker may couple the manifold to a second manifold and a female adapter (such as female adapter  940 ). In some examples, the worker may couple the manifold to a second manifold and an end cap (such as end cap  950 ). Coupling the manifold to other components of a manifold assembly may include coupling the components by a “press-and-click” method as described above. For example, the components may be aligned and compressed together to overcome the resistive force of a set of spring-biased clips, after which the components are coupled together. 
     At step  2018 , the worker couples the jet back to the jet body. Coupling the jet back to the jet body may include coupling the components of the jet assembly by a “press-and-click” method as described above. For example, the jet back and the jet body may be aligned and compressed together to overcome the resistive force of a set of spring-biased clips (such as spring-biased clips  328  in jet assembly  300 ), after which the jet back and the jet body are coupled together. 
     Installing Jet Assembly 
     This section describes steps of illustrative methods for assembling a hot tub jet assembly such as jet assembly  200 ; see  FIGS. 66 and 67 . Aspects and/or components of hot tub  100 , jet assembly  200 , manifold assembly  910 , and/or system  1700  may be utilized in the method steps described below. Where appropriate, reference may be made to components and systems that may be used in carrying out each step. These references are for illustration and are not intended to limit the possible ways of carrying out any particular step of the method. 
       FIG. 66  is a flowchart illustrating steps performed in an illustrative method of coupling a jet back to a jet body, and may not recite the complete process or all steps of the method. Although various steps of method  2100  are described below and depicted in  FIG. 66 , the steps need not necessarily all be performed, and in some cases may be performed simultaneously or in a different order than the order shown. Method  2100  includes coupling the jet back (such as jet back  202 ) to the jet body (such as jet body  204 ) and may performed as part of installing a jet assembly (such as jet assembly  200 ) and/or installing a hot tub plumbing system (such as system  1700 ). Additionally, or alternatively, method  2100  may be referred to as and/or may be included in a “press-and-click” method such as those described above. 
     At step  2102 , a worker aligns a jet back (such as jet back  122  and/or  202 ) with a jet body (such as jet body  124  and/or  204 ). In some examples, the jet back may already be coupled with tubing (such as tubing  1710 ) and/or the jet body may be installed in hot tub shell  104 . In some examples, aligning the jet back with the jet body may include positioning the jet back against the jet body. At step  2104 , the worker compresses the jet back against the jet body such that spring-biased clips (such as spring-biased clips  328  in jet assembly  300 ) on the jet back engage with a retaining feature (such as groove  330  on jet assembly  300 ) on the jet body. 
     For example, the spring-biased clips may be configured to flex outward, away from a default position, when a sloped lip (such as sloped lip  334  of jet assembly  300 ) slides over a proximate end of the jet body and along an external portion of the jet body. The spring-biased clips may be further configured to snap back into the default position when the sloped lip encounters the retaining feature on the jet body. In some examples, the spring-biased clips may engage with the retaining feature and prevent the jet back from sliding off of the jet body. Thus, the jet back and the jet body are coupled together. 
     In some examples, the jet back and the jet body may be configured to be able to be unlocked and/or uncoupled. Uncoupling the jet back from the jet body may be accomplished by moving the spring-biased clips away from the jet body and reversing steps  2104  and  2102 . For example, to uncouple the jet back from the jet body, the worker may move the spring-biased clips away from the default position and slide the jet back off of the jet body. In some examples, the worker may use a finger to move the spring biased clips and/or may use a tool. Releasably coupling the jet back and the jet body together may be advantageous as it may, among other advantages, allow the worker to uncouple a jet back that was coupled to the wrong jet body by mistake. 
       FIG. 67  is a flowchart illustrating steps performed in an illustrative method of coupling tubing to a jet back, and may not recite the complete process or all steps of the method. Although various steps of method  2200  are described below and depicted in  FIG. 67 , the steps need not necessarily all be performed, and in some cases may be performed simultaneously or in a different order than the order shown. Method  2200  includes coupling the tubing (such as tubing  120  or  1710 ) to the jet back (such as jet back  202 ) and may be performed as part of installing a jet assembly (such as jet assembly  200 ) and/or installing a hot tub plumbing system (such as system  1700 ). 
     At step  2202 , a worker aligns an end of a length of tubing with the air and/or water ingress ports (such as water ingress port  310  and/or air ingress port  312 ) on the jet back. At step  2204 , the worker slides the tubing over the air and water ingress ports. In some examples, step  2202  and/or step  2204  may include and/or may occur after dipping the end of the length of tubing in a lubricant (such as soapy water). For example, coupling the tubing to the ingress ports may include sliding the tubing over the end of the ingress ports and use of a lubricant may facilitate sliding the end of the tubing over the end of the air and/or water ingress ports. 
     In some examples, coupling the tubing to the jet back includes coupling the first portion of the tubing to the water ingress port of the jet back and the second portion of the tubing to the air ingress port of the jet back. For example, the tubing may be dual extrusion tubing and the first and second portions may be joined at a periphery. In some examples, the tubing may be dual extrusion tubing and the two portions of the tubing may be slid over the ends of the air and water ingress ports substantially simultaneously. In some examples, the tubing may include separate air and water tubing and the tubing may be slid over the ends of the air and water ingress ports substantially independently. For example, the water tubing may be slid over the end of the water ingress port and then the air tubing may be slid over the end of the air ingress port or vice versa. In other words, the tubing may be slid over the end of one ingress port and then over the end of the other ingress port. 
     At step  2206 , the worker places a dual aperture clamp (such as clamp  1800  or  1900 ) over the tubing where the tubing overlaps the air and water ingress ports. At step  2208 , the worker clamps the tubing to the ingress ports by compressing an end portion (such as end portion  1814  and/or  1914 ) of the clamp until a first and second set of teeth engage and compress the tubing against the ingress ports. The clamp ensures that the tubing does not slip off of the ingress ports of the jet back; the clamp cannot flex around a lip disposed or formed upon the water ingress port (such as lip  316  on jet assembly  300 ) and so cannot slip off of the set of ingress ports. The clamp compresses the tubing against the ingress ports and ensures a water- and/or air-tight seal between the tubing and the ingress ports. For example, a water- and air-tight seal can be achieved using the clamp and without the use of glue, primer, and/or other adhesives. 
     In some examples, the tubing is dual extrusion tubing and the clamp has a shape that is complementary to the shape of the tubing such that the clamp compresses all portions of the tubing. In some examples, the tubing includes separate air and water tubing and the clamp is shaped such that it can compress both the air tubing and the water tubing substantially separately and substantially simultaneously. 
     Installing Manifold Assembly 
     This section describes steps of illustrative methods for assembling portions of a hot tub manifold assembly such as manifold assembly  910 ; see  FIGS. 68, 69, 70 and 71 . Aspects and/or components of hot tub  100 , jet assembly  200 , manifold assembly  910 , and/or system  1700  may be utilized in the method steps described below. Where appropriate, reference may be made to components and systems that may be used in carrying out each step. These references are for illustration and are not intended to limit the possible ways of carrying out any particular step of the method. 
       FIG. 68  is a flowchart illustrating steps performed in an illustrative method of assembling a portion of a manifold assembly, and may not recite the complete process or all steps of the method. Although various steps of method  2300  are described below and depicted in  FIG. 68 , the steps need not necessarily all be performed, and in some cases may be performed simultaneously or in a different order than the order shown. Method  2300  includes coupling the manifold (such as manifold  920 ) to another component and may performed as part of installing a manifold assembly (such as manifold assembly  910 ) and/or installing a hot tub plumbing system (such as system  1700 ). Specifically, method  2300  includes coupling the manifold to a component which is downstream of the manifold and which may include a second manifold, a female adapter (such as female adapter  940 ), and/or an end cap (such as end cap  950 ). 
     At step  2302 , a worker aligns the manifold with another component. In some examples, the other component may be a second manifold, a female adapter, and/or an end cap. In some examples, the manifold and/or the other manifold may already be coupled with tubing (such as tubing  1710 ). In some examples, the female adapter may already be coupled with air and/or water supply lines (such as pipe  112  and/or air tubing  116 ). In some examples, aligning the manifold with the other component may include positioning the manifold against the other component. At step  2304 , the worker compresses the manifold against the other component such that spring-biased clips (such as clips  1032 ,  1040 ,  1432 ,  1448 ,  1228 ,  1234 ,  1328 ,  1334 ,  1628 , and/or  1634 ) on the other component engage with a retaining feature (such as retaining post  1038  and/or ridge  1046 ,  1438 , and/or  1448 ) on the manifold. 
     For example, the spring-biased clips may be configured to flex away from a default position when a sloped lip (such as lip  1036 ,  1044 ,  1436 ,  1454 ,  1232 ,  1238 ,  1332 ,  1338 ,  1632 , and/or  1638 ) slides along an external portion of the manifold and over the retaining feature. The spring-biased clips may be further configured to snap back into the default position when the sloped lip passes the retaining feature on the manifold. In some examples, the spring-biased clips may engage with the retaining feature and prevent the other component from sliding off of the manifold. Thus, the manifold and the other component are coupled together. 
     In some examples, the manifold and the other component may be configured to be able to be unlocked and/or uncoupled. Uncoupling the manifold from the other component may be accomplished by moving the spring-biased clips away from the default position and reversing steps  2304  and  2302 . For example, to uncouple the manifold from the other component, the worker may move the spring-biased clips away from the default position and slide the other component off of the manifold. In some examples, the worker may use a finger to move the spring-biased clips and/or may use a tool. Releasably coupling the manifold and the other component together may be advantageous as it may, among other advantages, allow the worker to uncouple a manifold that was coupled to the wrong component by mistake. 
       FIG. 69  is a flowchart illustrating steps performed in an illustrative method of assembling another portion of a manifold assembly, and may not recite the complete process or all steps of the method. Although various steps of method  2400  are described below and depicted in  FIG. 69 , the steps need not necessarily all be performed, and in some cases may be performed simultaneously or in a different order than the order shown. Method  2400  includes coupling the manifold (such as manifold  920 ) to another component and may performed as part of installing a manifold assembly (such as manifold assembly  910 ) and/or installing a hot tub plumbing system (such as system  1700 ). Specifically, method  2400  includes coupling the manifold to a component which is upstream of the manifold and which may include a second manifold and/or a male adapter (such as male adapter  930 ). 
     At step  2402 , a worker aligns the manifold with another component. In some examples, the other component may be a second manifold and/or a male adapter. In some examples, the manifold and/or the other manifold may already be coupled with tubing (such as tubing  1710 ). In some examples, the male adapter may already be coupled with air and/or water supply lines (such as pipe  112  and/or air tubing  116 ). In some examples, aligning the manifold with the other component may include positioning the manifold against the other component. At step  2404 , the worker compresses the manifold against the other component such that spring-biased clips (such as clips  1032 ,  1040 ,  1432 , and/or  1448 ) on the manifold engage with a retaining feature (such as retaining post  1038  and/or  1130  and/or ridge  1046 ,  1438 ,  1448 ,  1132 ,  1524 , and/or  1534 ) on the other component. 
     For example, the spring-biased clips may be configured to flex away from a default position when a sloped lip (such as lip  1036 ,  1044 ,  1436 , and/or  1454 ) slides along an external portion of the other component and over the retaining feature. The spring-biased clips may be further configured to snap back into the default position when the sloped lip passes the retaining feature on the other component. In some examples, the spring-biased clips may engage with the retaining feature and prevent the manifold from sliding off of the other component. Thus, the manifold and the other component are coupled together. 
     In some examples, the manifold and the other component may be configured to be able to be unlocked and/or uncoupled. Uncoupling the manifold from the other component may be accomplished by moving the spring-biased clips away from the default position and reversing steps  2404  and  2402 . For example, to uncouple the manifold from the other component, the worker may move the spring-biased clips away from the default position and slide the manifold off of the other component. In some examples, the worker may use a finger to move the spring-biased clips and/or may use a tool. Releasably coupling the manifold and the other component together may be advantageous as it may, among other advantages, allow the worker to uncouple a manifold that was coupled to the wrong component by mistake. 
       FIG. 70  is a flowchart illustrating steps performed in an illustrative method of attaching tubing to a manifold assembly, and may not recite the complete process or all steps of the method. Although various steps of method  2500  are described below and depicted in  FIG. 70 , the steps need not necessarily all be performed, and in some cases may be performed simultaneously or in a different order than the order shown. Method  2500  includes coupling the tubing (such as tubing  120  or  1710 ) to the manifold (such as manifold  920 ) and may be performed as part of installing a manifold assembly (such as manifold assembly  910 ) and/or installing a hot tub plumbing system (such as system  1700 ). 
     At step  2502 , a worker aligns an end of a length of tubing with the air and/or water egress ports (such as water egress port  1016  and/or  1416  and/or air egress port  1018  and/or  1418 ) on the manifold. At step  2504 , the worker slides the tubing over the air and water egress ports. In some examples, step  2502  and/or step  2504  may include and/or may occur after dipping the end of the length of tubing in a lubricant (such as soapy water). For example, coupling the tubing to the egress ports may include sliding the tubing over the end of the egress ports and use of a lubricant may facilitate sliding the end of the tubing over the end of the air and/or water egress ports. 
     In some examples, coupling the tubing to the manifold includes coupling the first portion of the tubing to the water egress port of the manifold and the second portion of the tubing to the air egress port of the manifold. For example, the tubing may be dual extrusion tubing and the first and second portions may be joined at a periphery. In some examples, the tubing may be dual extrusion tubing and the two portions of the tubing may be slid over the ends of the air and water egress ports substantially simultaneously. In some examples, the tubing may include separate air and water tubing and the tubing may be slid over the ends of the air and water egress ports substantially independently. For example, the water tubing may be slid over the end of the water egress port and then the air tubing may be slid over the end of the air egress port or vice versa. In other words, the tubing may be slid over the end of one egress port and then over the end of the other egress port. 
     At step  2506 , the worker places a dual aperture clamp (such as clamp  1800  or  1900 ) over the tubing where the tubing overlaps the air and water egress ports. At step  2508 , the worker clamps the tubing to the egress ports by compressing an end portion (such as end portion  1814  and/or  1914 ) of the clamp until a first and second set of teeth engage and compress the tubing against the egress ports. The clamp ensures that the tubing does not slip off of the egress ports of the manifold; the clamp cannot flex around a lip disposed on the water egress port (such as lip  1020 ) and so cannot slip off of the set of egress ports. The clamp compresses the tubing against the egress ports and ensures a water- and/or air-tight seal between the tubing and the egress ports. For example, a water- and air-tight seal can be achieved using the clamp and without the use of glue, primer, and/or other adhesives. 
     In some examples, the tubing is dual extrusion tubing and the clamp has a shape that is complementary to the shape of the tubing such that the clamp compresses all portions of the tubing. In some examples, the tubing includes separate air and water tubing and the clamp is shaped such that it can compress both the air tubing and the water tubing substantially separately and substantially simultaneously. 
       FIG. 71  is a flowchart illustrating steps performed in an illustrative method of coupling air and water sources to manifold adapters in a manifold assembly, and may not recite the complete process or all steps of the method. Although various steps of method  2600  are described below and depicted in  FIG. 71 , the steps need not necessarily all be performed, and in some cases may be performed simultaneously or in a different order than the order shown. Method  2600  includes installing air and water supply lines (such as pipe  112  and/or air tubing  116 ) and may be performed as part of installing a manifold assembly (such as manifold assembly  910 ) and/or installing a hot tub plumbing system (such as system  1700 ). 
     At step  2602 , a worker couples a first end of a water supply line or pipe (such as pipe  112 ) to a first male adapter (such as male adapter  930 ). In some examples, any suitable mechanism for coupling the water supply line to the adapter may be used. In some examples, this step may include the application of glue, primer, and/or any other suitable adhesive to the water supply line and/or the adapter. For example, glue may be applied to the outside of the end of the water supply line before it is inserted into the end of the water conduit of the male adapter. In some examples, this step may include the application of a clamp and/or any other suitable connection mechanism. 
     At step  2604 , the worker couples a first end of an air supply line or air tubing (such as air tubing  116 ) to the first male adapter (such as male adapter  930 ). In some examples, any suitable mechanism for coupling the air supply line to the adapter may be used. In some examples, this step may include the application of glue, primer, and/or any other suitable adhesive to the air supply line and/or the adapter. For example, primer may be applied to the outside of the end of the air supply line before it is inserted into the end of the air conduit of the male adapter. In some examples, this step may include the application of a clamp and/or any other suitable connection mechanism. 
     At step  2606 , the worker couples a second end of the water supply line to a valve (such as valve  108 ) and/or a female adapter (such as female adapter  940 ). In some examples, the water supply line may be connecting a first manifold assembly to a water source and the second end of the water supply line may couple with a valve and/or with a female adapter which couples with the valve. In some examples, the water supply line may be connecting a first manifold assembly to a second manifold assembly and the water supply line may couple with a female adapter. In some examples, any suitable mechanism for coupling the water supply line to the valve and/or adapter may be used. Step  2606  may be generally similar to step  2602 . For example, step  2606  may include the application of glue, primer, and/or any other suitable adhesive to the water supply line, the valve, and/or the adapter. For example, glue may be applied to the outside of the end of the water supply line before it is inserted into the end of a water conduit of the female adapter and/or the valve. In some examples, this step may include the application of a clamp and/or any other suitable connection mechanism. 
     At step  2608 , the worker couples a second end of the air supply line to an air supply (such as air supply  114 ) and/or a female adapter (such as female adapter  940 ). In some examples, the air supply line may be connecting a first manifold assembly to an air supply and the second end of the air supply line may couple with the air supply and/or with a female adapter which couples with the air supply. In some examples, the air supply line may be connecting a first manifold assembly to a second manifold assembly and the air supply line may couple with a female adapter. In some examples, any suitable mechanism for coupling the air supply line to the air supply and/or adapter may be used. Step  2608  may be generally similar to step  2604 . For example, step  2608  may include the application of glue, primer, and/or any other suitable adhesive to the air supply line, the air supply, and/or the adapter. For example, primer may be applied to the outside of the end of the water supply line before it is inserted into the end of an air conduit of the female adapter and/or the air supply. In some examples, this step may include the application of a clamp and/or any other suitable connection mechanism. 
     At optional step  2610 , the worker couples the first male adapter to a first manifold (such as manifold  920 ). Coupling the first male adapter to the manifold may include any suitable mechanism. For example, the first male adapter and the manifold may be coupled by a “press-and-click” method described above. At optional step  2612 , the worker couples the female adapter to a valve (such as valve  108 ), an air supply (such as air supply  114 ), and/or a second manifold (such as manifold  920 ). Coupling the female adapter to the valve, the air supply, and/or the second manifold may include any suitable mechanism. For example, the female adapter and the second manifold may be coupled by a “press-and-click” method described above. In some examples, the female adapter may be coupled with the valve and/or the air supply using a “press-and-click” method such as described above. 
     E. Illustrative Jet Assemblies Including a Spring-Biased Ring 
     With reference to  FIGS. 72-78 , this section describes illustrative jet assemblies including a jet body configured to couple to a jet back via a press-and-click fitting mechanism including a spring-biased ring. 
     Straight Back Embodiment 
     Straight back jet assembly  2700  is an illustrative embodiment of general jet assembly  200 . Jet assembly  2700  may be substantially similar in at least some respects to jet assembly  200  and/or to other jet assembly examples described above. Accordingly, similar components may be labeled with similar reference numbers and only an abbreviated discussion of some features is provided here. 
       FIGS. 72-74  depict various views of jet assembly  2700 . Specifically,  FIG. 72  is an exploded side view of jet assembly  2700 ,  FIG. 73  is an exploded sectional side view of the jet assembly, and  FIG. 74  is an isometric view of the jet assembly. As shown in these views, jet assembly  2700  includes a jet back  2702  and a jet body  2704 . Jet assembly  2700  may further include a jet insert, also referred to as a jet face (not shown). Jet back  2702  may be referred to as a straight-back jet back, or a straight jet back. Jet back  2702  is an example of jet back  202  described above, jet body  2704  is an example of jet body  204  described above, and a compatible jet insert would be an example of jet insert  206  described above. 
     Jet back  2702  includes two parallel ingress ports: a water ingress port  2710  and an air ingress port  2712 . Water ingress port  2710  is larger than air ingress port  2712  and is substantially centered on a longitudinal axis  2714  of the jet back. 
     Water ingress port  2710  (also referred to as a barb) includes a lip or ridge  2716 . Lip  2716  may include any suitable structure configured to ensure a water-tight seal between water ingress port  2710  and a length of tubing (such as tubing  120 ). In the example depicted in  FIGS. 72-74 , lip  2716  includes a sloped ridge having a vertex distal an exterior surface of water ingress port  2710 , but in other examples, the lip may have another suitable structure. 
     Air ingress port  2712  (also referred to as a barb) is parallel to water ingress port  2710  and is offset from the center of jet back  2702 . In some examples, air ingress port  2712  may include a lip or other feature configured to ensure a seal. In some examples, an external portion of air ingress port  2712  may be smooth, as in the example depicted in  FIGS. 72-74 . 
     In the example depicted in  FIGS. 72-74 , jet back  2702  is configured to couple with dual extrusion tubing having two fluid passages joined at a periphery, but in other examples the jet back may be configured to couple with any other suitable type of tubing. Dimensions of the air and water ingress ports and/or the spacing between the ingress ports may be selected to facilitate coupling with desired tubing. 
     Jet back  2702  further includes a central portion  2718  configured to create a water-tight seal with jet body  2704 . Central portion  2718  is in direct fluid communication with water ingress port  2710  and air ingress port  2712 , and may have any shape suitable for a selected application and/or for the characteristics of the jet body. For example, central portion  2718  may be substantially cylindrical, as in the example depicted in  FIGS. 72-74 . In other examples, the central portion may be rectangular, triangular, elliptical, and/or have any other suitable shape. 
     Jet body  2704  includes an upstream portion  2720  and a downstream portion  2722 . Upstream portion  2720  may include any suitable structure configured to be at least partially disposed within central portion  2718  of the jet back. For example, as shown in  FIGS. 72-74 , upstream portion  2720  may be substantially cylindrical. In some examples, downstream portion  2722  may have substantially the same cross-sectional shape and/or size as upstream portion  2720 . For example, downstream portion  2722  may also be substantially cylindrical, as in  FIGS. 72-74 . Downstream portion  2722  may further include any suitable structure configured to engage with hot tub shell  104  and/or a jet insert. For example, downstream portion  2722  may include a flange  2724 . Downstream portion  2722  is discussed in further detail below. 
     One or more openings  2726  are formed within jet back  2702  adjacent a downstream end  2728  of the jet back. Openings  2726  are separated by unmodified portions  2727  of the jet back. Openings  2726  are configured to receive one or more protrusions  2730  projecting from an exterior surface  2731  of jet body  2704 . Protrusions  2730  may also be referred to as hooks, prongs, or projections. Openings  2726  are sized and shaped to define a resilient ring  2732  spaced from downstream end  2728  and supported above the downstream end by unmodified portions  2727 . As shown in  FIG. 74 , when protrusions  2730  are disposed within openings  2726 , the protrusions engage ring  2732  such that the ring tends to prevent the protrusions from sliding out of the openings (e.g., in a downstream direction). In this manner, ring  2732  and protrusions  2730  couple the jet back  2702  to jet body  2704 . 
     Ring  2732  is configured to be resilient (e.g., spring biased), such that the ring is at least partially deformable and/or translatable in at least a radial direction. For example, a shape of ring  2732  may be deformed in at least one direction in response to a suitable force, and/or the ring may be displaced in a radial and/or axial direction (e.g., by deformation of unmodified portions  2727 ) in response to a suitable force. The resiliency of ring  2732  allows jet body  2704  to be coupled to jet back  2702  in a press-and-click manner. Specifically, inserting jet body  2704  into jet back  2702  causes protrusions  2730  to push against ring  2732 , urging at least some portions of the ring radially outward (e.g., away from longitudinal axis  2714 ) and thereby allowing the protrusions to pass through the ring to be received in openings  2726 . With protrusions  2730  received in openings  2726 , the protrusions no longer deform ring  2732 , and the resilient bias of the ring restores the ring to its typical or default shape (e.g., the cross-sectional shape of jet back  2702 ) and/or position. 
     Ring  2732  and protrusions  2730  may each have any suitable shape. In some examples, the ring and the protrusions are shaped in a manner that facilitates insertion of the jet body into the jet back and inhibits removal of the jet body from the jet back. In other words, the ring and the protrusions may be shaped such that the protrusions are relatively easy to move past the ring into the openings, but difficult or impossible to move out of the openings past the ring without intervention (e.g., manually deforming and/or displacing the ring and/or protrusions). In the example depicted in  FIGS. 72-74 , protrusions  2730  are tapered such that the protrusions are longer radially at a downstream end than at an upstream end, and ring  2732  is tapered such that its inner diameter increases in the downstream direction. Accordingly, protrusions  2730  each have a sloped surface  2733 , and ring  2732  has a complementary sloped lip  2734 . When jet body  2704  and jet back  2702  are aligned and pushed together, sloped surface  2733  of protrusions  2730  slide against sloped lip  2734  of ring  2732 , flexing the ring outward. The complementary tapered shapes of ring  2732  and protrusions  2730  facilitate deformation of the ring by the projections during insertion of jet body  2704  into jet back  2702 . When protrusions  2730  are within openings  2726 , a downstream surface  2735  of each protrusion engages ring  2732 , thereby retaining the jet body within the jet back. In other examples, however, ring  2732  and/or protrusions  2730  may be shaped differently. 
     Protrusions  2730  may be substantially rigid, substantially as resilient as ring  2732 , more resilient than ring  2732 , or less resilient than ring  2732 . In some examples, protrusions  2730  are resilient and ring  2732  is substantially rigid. The protrusions may extend from jet body  2704  in a substantially orthogonal and/or transverse direction, as in the example depicted in  FIGS. 72-74 , or in any other suitable direction(s). 
     The degree of resiliency of ring  2732  may be at least partially determined by the material of the ring, the axial length of the ring, the size (e.g., circumferential extent) of openings  2726  and/or unmodified portions  2727  of jet back  2702  connecting the ring to the jet back, and/or other factors. Any suitable material(s) and dimensions may be selected. In the example depicted in  FIGS. 72-74 , openings  2726  comprise channels having a relatively long circumferential extent, and unmodified portions  2727  have a much shorter circumferential extent than do the openings. In other examples, the sizes of the openings and/or unmodified portions may be changed, which may lead to a corresponding change in the resiliency of the ring. Jet back  2702  may include any suitable number of openings  2726  and unmodified portions  2727 . 
     In some examples, protrusions  2730  and openings  2726  are sized and shaped to allow jet body  2704  to rotate relative to jet back  2702  while maintaining a water-tight and/or air-tight seal. For example, in the embodiment depicted in  FIGS. 72-74 , the long circumferential extent of openings  2726  defines an angular span over which jet body  2704  can rotate while protrusions  2730  are within the openings. This may facilitate installation and/or maintenance of the jet assembly in a hot tub or other system. For example, it may allow a worker to prevent adjacent jet assemblies from interfering with each other by rotating one or more of the jet assemblies as needed. 
     In the example depicted in  FIGS. 72-74 , ring  2732  is integral with jet back  2702 , such that the ring is defined by openings  2726  within the jet back and supported by unmodified portions  2727  of the jet back. In other examples, the ring is not integral with the jet back, and is attached to the jet back by a suitable connector(s). 
     In the example depicted in  FIGS. 72-74 , ring  2732  has a circular and/or annular shape. In other examples, however, the ring may have another shape (e.g., triangular, rectangular, elliptical, polygonal, etc.). The ring may have a shape similar or identical to a cross-sectional shape of the jet back, or the ring may have a different shape from the cross-sectional shape of the jet back. 
     Jet body  2704  includes recesses  2736  configured to contain one or more O-rings  2738 . Recesses  2736  may include any structure suitable for retaining O-rings  2738  depending, e.g., on characteristics of the jet back, jet body, and/or O-rings. For example, in the embodiment depicted in  FIGS. 72-74 , recesses  2736  comprise narrow circumferential channels within upstream portion  2720 . In this example, recesses  2736  are configured such that the outside edge of the O-ring is flush with, or extends slightly beyond, the surface of the upstream portion of the jet body. Allowing the O-ring to extend slightly beyond adjacent surfaces of the jet body may ensure a water-tight seal by facilitating compression of the O-ring between an inner surface of the jet back and the sides of recesses  2736 . Jet body  2704  may include any suitable number of recesses and/or O-rings. 
     Jet back  2702  also includes a spacing mechanism configured to ensure sufficient space between a proximate end  2740  of upstream portion  2720  of jet body  2704  and an inner wall  2742  of jet back  2702 . The spacing mechanism may include any suitable structure depending on the characteristics of the jet body and the jet back. In the example depicted in  FIG. 73 , jet back  2702  includes a plurality of spacers  2744 . Any suitable number of spacers  2744  may be provided, including a single continuous spacer extending circumferentially around some or all of inner wall  2742 . 
     Jet body  2704  has a main aperture  2766  connecting a main cavity  2758  with a receiving chamber  2768 . Receiving chamber  2768  is primarily disposed within downstream portion  2722  and includes a substantially cylindrical cavity configured for receiving at least a portion of a jet insert. In other examples, receiving chamber  2768  may include a rectangular and/or triangular cavity, and/or any other suitably shaped cavity (depending, e.g., on the shape of the jet insert). Inner wall  2769  of receiving chamber  2768  has a threaded portion  2770  configured for threadedly receiving at least a portion of a jet insert. Threaded portion  2770  may extend longitudinally along any suitable fraction of inner wall  2769 . In the example depicted in  FIG. 73 , threaded portion  2770  is disposed proximate aperture  2766 , but in other examples, the threaded portion may be disposed at another suitable location. The position of threaded portion  2770  may be selected to enable and/or ensure a desired distance between the jet insert and aperture  2766 . Jet body  2704  may be configured to receive any suitable type(s) of jet insert. 
     As shown in  FIGS. 73-74 , a recess or channel  2776  is formed in a downstream surface  2778  of flange  2724  of jet body  2704 . In the example depicted in  FIGS. 73-74 , channel  2776  has a rectangular cross-sectional shape, but in other examples, the channel may have a different cross-sectional shape, and/or may have a different cross-sectional shape at different points. Channel  2776  is configured to facilitate coupling between jet body  2704  and a jet insert (not shown). 
     Channel  2776  includes a plurality of molded ribs  2780  (see  FIG. 74 ) configured to engage with the jet insert such that the jet insert is inhibited from rotating relative to flange  2724 . In this manner, molded ribs  2780  act as stops to prevent the jet insert from unscrewing from threaded portion  2770  of jet body  2704 , thereby increasing the security of the connection between the jet insert and the jet body. In the example depicted in  FIG. 74 , molded ribs  2780  have a height that is smaller than the depth of channel  2776  (e.g., the molded ribs do not extend all the way from the bottom of the channel to the top of the channel). This height may allow the jet insert to be screwed into threaded portion  2770  during installation, while inhibiting inadvertent unscrewing of the jet insert from the threaded portion. In general, molded ribs  2780  may have any suitable size and shape for engaging with the jet insert in this manner. 
     As described above, jet back  2702  and jet body  2704  may be coupled together by aligning the jet back and the jet body and compressing the jet back and jet body together to overcome the resistive force of spring-biased ring  2732 . 
     Each of the components of jet assembly  2700  (e.g., jet back  2702 , jet body  2704 , a jet insert) may comprise any suitable material(s). For example, the components may comprise any suitable thermoplastic polymer such as polyvinyl chloride (PVC), acrylonitrile butadiene styrene (ABS), and/or any other suitable materials having similar properties (i.e., stiffness etc.). The components may be manufactured using any suitable process. For example, the manufacturing process may include the use of injection molding, compression molding, and/or extrusion methods. In some examples, each component may be injection molded out of PVC. 
     In some examples, jet assembly  2700  may include a nozzle configured to, e.g., increase the speed of a water stream, control a direction of the water stream, and/or merge streams of air and water. See, e.g., the description of nozzle  308  above. 
     Angled Back Embodiment 
       FIGS. 75-76  depict another illustrative jet assembly  2800 . Jet assembly  2800 , which is another example of jet assembly  200 , includes a jet back  2802 , a jet body  2804 , and may further include a jet insert. Jet body  2804  and jet back  2802  may be substantially similar in at least some respects to jet body  2704  and jet back  2702 , and accordingly the description provided below is abbreviated. In some examples, jet body  2804  and jet body  2704  are substantially identical and/or are interchangeable. 
       FIG. 75  is an exploded side view of jet assembly  2800 , and  FIG. 26  is an exploded sectional view of jet assembly  2800 . As shown in these views, jet back  2802  is an angled jet back, having a water ingress port  2810  and an air ingress port  2812  that are not parallel to a longitudinal axis  2814  of the jet back. Water ingress port  2810  and air ingress port  2812  may be substantially similar to, e.g., water ingress port  610  and air ingress port  612  described above. For example, water ingress port  2810  may include a base portion  2816  substantially parallel with and centered on longitudinal axis  2814 , and an extended portion  2818  angled relative to the base portion. In the example depicted in  FIGS. 75-76 , extended portion  2818  is oriented at an approximately 90-degree angle relative to base portion  2816 , but in other examples, the extended portion and base portion may form any other suitable angle. Water ingress portion  2810  includes a lip  2819  configured to form a water-tight seal between the water ingress port and a length of tubing (e.g., tubing  120 ). 
     Air ingress port  2812  is substantially parallel to extended portion  2818 . In some examples, air ingress port  2812  includes a lip configured to form an air-tight seal with tubing. 
     As with previous embodiments, jet back  2802  includes a central portion  2820  in direct fluid communication with water ingress port  2810  and air ingress port  2812  and configured to create a water-tight seal with jet body  2804 . Jet body  2804  includes an upstream portion  2821  and a downstream portion  2822 . Upstream portion  2821  is configured to be at least partially disposed within central portion  2820 . Downstream portion  2822  includes a flange  2824 , which includes a channel  2825 . Channel  2825  may include molded ribs similar or identical to molded ribs  2780  (not shown). 
     Jet body  2804  and jet back  2802  are configured to couple together in substantially the same manner as jet body  2704  and jet back  2702 . Accordingly, jet back  2802  includes one or more openings  2826  separated by unmodified portions  2827  of the jet back. Openings  2826  are disposed adjacent a downstream end  2828  of the jet back and are configured to receive one or more protrusions  2830  projecting from an exterior surface  2831  of jet body  2804 . Openings  2826  define a resilient ring  2832  spaced from downstream end  2828 . 
     Like jet body  2704 , jet body  2804  includes recesses  2836  configured to hold O-rings  2838 . Proximate end  2840  of jet body  2804  are retained above inner wall  2869  of jet back  2802  by spacers  2844  disposed on the inner wall. Jet body  2804  has a main cavity  2858 , a main aperture  2866 , and a receiving chamber  2868 . 
     Inner wall  2869  of receiving chamber  2868  has a threaded portion  2870  configured for threadedly receiving at least a portion of a jet insert. Jet body  2804  may be configured to receive any suitable type(s) of jet insert. 
     Illustrative Jet Body Shapes 
       FIGS. 77-78  are sectional views depicting illustrative jet bodies suitable for use in assemblies  2700  and  2800 . These exemplary jet bodies have different shapes and/or sizes than the example jet bodies depicted in  FIGS. 72-76 . Specifically,  FIG. 77  is a sectional view depicting an illustrative jet body  2902  that has a downstream end  2904  having a first diameter, and a threaded portion  2906  having a second diameter smaller than the first diameter. In some examples, the first diameter of downstream end  2904  is approximately four inches, but other values are possible. 
       FIG. 78  is a sectional view depicting an illustrative jet body  2912  that has a downstream end  2914  having a third diameter, and a threaded portion  2916  having a fourth diameter smaller than the third diameter. In some examples, the third diameter of downstream end  2914  is approximately five inches, but other values are possible. 
     Aside from the diameters of the downstream ends and threaded portions, jet bodies  2902  and  2912  may be substantially similar to jet body  2802  and/or jet body  2702 . Jet bodies  2902  and  2912  may be configured to be coupled to jet back  2804 , jet back  2704 , and/or any other suitable jet back. 
     In general, any suitable diameter may be selected for the downstream end of the jet body, and any suitable diameter may be selected for the threaded portion of the jet body. The downstream-end diameter and the threaded-portion diameter, and/or the difference between the downstream-end and threaded-portion diameters, may be selected based on characteristics of a jet insert to be coupled to the jet body, and/or on any other suitable basis. 
     F. Additional Examples and Illustrative Combinations 
     This section describes additional aspects and features of a hot tub plumbing system, its components and its methods of assembly, presented without limitation as a series of paragraphs, some or all of which may be alphanumerically designated for clarity and efficiency. Each of these paragraphs can be combined with one or more other paragraphs, and/or with disclosure from elsewhere in this application, including the materials incorporated by reference in the Cross-References, in any suitable manner. Some of the paragraphs below expressly refer to and further limit other paragraphs, providing without limitation examples of some of the suitable combinations. 
     A. A hot tub jet assembly, comprising: 
     a jet body configured to receive separate streams of air and water, to merge the separate streams of air and water together to form a mixed stream of air and water, and to provide the mixed stream of air and water from an outlet aperture; 
     a jet back configured to couple to the jet body and to provide the separate streams of air and water to the jet body, the jet back including:
         a central portion configured to create a water tight seal with the jet body;   an attachment mechanism extending from a first end of the central portion and configured to attach the jet back to the jet body in a secure manner; and   a pair of parallel hollow protrusions extending from a second end of the central portion, each protrusion configured to receive one of the separate streams of air and water from a dual extrusion tube.       

     A1. The jet assembly of paragraph A, wherein the attachment mechanism includes at least two spring-biased clips extending from the first end of the central portion of the jet back, each clip configured to snap into spring-biased engagement with a retaining ridge disposed at a periphery of the jet body. 
     A2. The jet assembly of paragraph A, wherein the jet body includes at least one O-ring disposed around a periphery of the jet body, and wherein an inner cylindrical surface of the central portion of the jet back is configured to fit around the O-ring in a substantially water tight compression fit. 
     A3. The jet assembly of paragraph A, further comprising a jet insert configured fit within an aperture of a hot tub body, to receive the mixed stream of air and water from the jet body and to channel the mixed stream of air and water into an interior portion of the hot tub body through the aperture. 
     A4. The jet assembly of paragraph A, wherein the parallel hollow protrusions define longitudinal axes oriented parallel to a longitudinal axis defined by the central portion. 
     A5. The jet assembly of paragraph A, wherein the parallel hollow protrusions define longitudinal axes oriented at a non-zero angle relative to a longitudinal axis defined by the central portion. 
     A6. The jet assembly of paragraph A5, wherein the non-zero angle is 90 degrees. 
     AA. A hot tub jet back configured to provide separate streams of air and water to a hot tub jet body, comprising: 
     a central portion configured to create a water tight seal with the jet body; 
     an attachment mechanism extending from a first end of the central portion and configured to attach the jet back to the jet body in a secure manner; and 
     a pair of parallel hollow fluid ports extending from a second end of the central portion, each protrusion configured to receive one of the separate streams of air and water from a dual extrusion tube. 
     AA1. The jet back of paragraph AA, wherein the attachment mechanism includes at least two opposed, spring-biased clips extending from the first end of the central portion of the jet back, each opposed clip configured to snap into spring-biased engagement with a complementary retaining ridge. 
     AA2. The jet back of paragraph AA1, further comprising a hot tub jet body, wherein the jet body includes at least one O-ring and a retaining ridge disposed around a periphery of the jet body, an inner cylindrical surface of the central portion of the jet back is configured to fit around the O-ring in a substantially water tight compression fit, and the opposed clips of the jet back are configured to snap into spring-biased engagement with the retaining ridge of the jet body. 
     AA3. The jet back of paragraph AA2, further comprising a hot tub jet insert configured to fit within an aperture of a hot tub body, to receive the mixed stream of air and water from the hot tub jet body and to channel the mixed stream of air and water into an interior portion of the hot tub body through the aperture. 
     AB. A hot tub jet assembly, comprising: 
     a jet back including first and second parallel, hollow fluid receiving ports extending from one end, wherein the first and second ports are configured to receive a stream of air and a stream of water, respectively, from a dual extrusion tube carrying both streams in adjacent portions of the tube, the jet back further including a plurality of spring-biased clips extending from another end of the jet back and configured to engage securely with a complementary ridge. 
     AB1. The jet assembly of paragraph AB, further comprising a jet body configured to engage securely with the jet back, to receive the streams of air and water from the jet back, to merge the separate streams of air and water together to form a mixed stream of air and water, and to provide the mixed stream of air and water from an outlet aperture. 
     AB2. The jet assembly of paragraph AB1, further wherein the spring-biased clips are configured to engage securely with a complementary ridge formed on the jet body. 
     AB3. The jet assembly of paragraph AB2, wherein the at least two spring-biased clips include four spring-biased clips evenly spaced around a periphery of the jet back. 
     AB4. The jet assembly of paragraph AB2, wherein the jet body includes two O-rings disposed around a periphery of the jet body, and wherein the jet back is configured to engage securely with the jet body in a substantially water tight manner when the spring-biased clips of the jet back are engaged with the complementary ridge of the jet body. 
     B. A hot tub air and water supply manifold, comprising: 
     a water conduit defining a first longitudinal axis and configured to receive water from a water supply line; 
     at least one air conduit defining a second longitudinal axis parallel to the first longitudinal axis and configured to receive air from an air supply line, the air conduit having a periphery joined to a periphery of the water conduit; 
     a first water egress port in fluid communication with the water conduit; 
     a first air egress port in fluid communication with the air conduit; 
     wherein the first water egress port and the first air egress port are disposed substantially parallel and adjacent to each other, and are configured to channel streams of water and air, respectively, to a first dual extrusion tube. 
     B1. The supply manifold of paragraph B, wherein the first water egress port and the first air egress port are both oriented substantially perpendicular to the water conduit and to the air conduit. 
     B2. The supply manifold of paragraph B, wherein the at least one air conduit includes a first air conduit joined to a first portion of the periphery of the water conduit, and a second air conduit joined to a second portion of the periphery of the water conduit, wherein the first air egress port is in fluid communication with the first air conduit, and further comprising: 
     a second water egress port in fluid communication with the water conduit; 
     a second air egress port in fluid communication with the second air conduit; 
     wherein the second water egress port and the second air egress port are disposed substantially parallel and adjacent to each other and are configured to channel streams of water and air, respectively, to a second dual extrusion tube. 
     B3. The supply manifold of paragraph B2, wherein the first portion of the periphery of the water conduit and the second portion of the periphery of the water conduit are separated from each other by approximately 180 degrees. 
     B4. The supply manifold of paragraph B2, further comprising a first spring-biased clip extending from a peripheral portion of a distal end of the first air conduit and a second spring-biased clip extending from a peripheral portion of a distal end of the second air conduit, and wherein the first and second spring-biased clips are respectively configured to engage complementary retaining ridges disposed at peripheral portions of first and second air conduits of an adjacent air and water supply manifold. 
     B5. The supply manifold of paragraph B2, further comprising a first retaining ridge disposed at a peripheral portion of the first air conduit and a second retaining ridge disposed at a peripheral portion of the second air conduit, wherein the first retaining ridge is configured to engage securely with a spring-biased clip extending from a first air conduit of an adjacent air and water supply manifold, and the second retaining ridge is configured to engage securely with a spring-biased clip extending from a second air conduit of the adjacent air and water supply manifold. 
     BA. A hot tub air and water supply manifold system, comprising: 
     a male manifold adapter, including:
         a male manifold adapter water conduit defining a first longitudinal axis and configured to receive water from a water supply pipe; and   a first male manifold adapter air conduit defining a second longitudinal axis parallel to the first longitudinal axis, the first male manifold adapter air conduit having a periphery joined to a periphery of the male manifold adapter water conduit;       

     a manifold body, including:
         a manifold body water conduit having a first end configured to connect with one end of the male manifold adapter water conduit in a water tight manner with a longitudinal axis of the manifold body water conduit collinear with the first longitudinal axis;   a first manifold body air conduit having a first end configured to connect with one end of the first male manifold adapter air conduit in an air tight manner with a longitudinal axis of the first manifold body air conduit collinear with the second longitudinal axis;   a first water egress port in fluid communication with the manifold body water conduit; and   a first air egress port in fluid communication with the first manifold body air conduit;       

     wherein the first water egress port and the first air egress port are disposed substantially parallel to each other, and are configured to channel respective streams of water and air to a first dual extrusion tube. 
     BA1. The manifold system of paragraph BA, further comprising an end cap including a water conduit end cap configured to attach securely to a second end of the manifold body water conduit and to prevent passage of water, and a first air conduit end cap configured to attach securely to a second end of the first manifold body air conduit and to prevent passage of air. 
     BA2. The supply manifold of paragraph BA, wherein the first water egress port and the first air egress port are each oriented perpendicular to the first longitudinal axis. 
     BA3. The supply manifold of paragraph BA, wherein the male manifold adapter includes:
         a second male manifold adapter air conduit defining a third longitudinal axis parallel to the first and second longitudinal axes, the second male manifold adapter air conduit having a periphery joined to the periphery of the male manifold adapter water conduit; and       

     wherein the manifold body includes:
         a second manifold body air conduit having a first end configured to connect with one end of the second male manifold adapter air conduit in an air tight manner with a longitudinal axis of the second manifold body air conduit collinear with the third longitudinal axis;   a second water egress port in fluid communication with the manifold body water conduit; and   a second air egress port in fluid communication with the second manifold body air conduit;       

     wherein the second water egress port and the second air egress port are disposed substantially parallel to each other, and are configured to channel respective streams of water and air to a second dual extrusion tube. 
     BA4. The supply manifold of paragraph BA, wherein the male manifold adapter includes a pair of male manifold adapter air conduits, each defining a separate longitudinal axis parallel to the first longitudinal axis, each having a periphery joined to a periphery of the male manifold adapter water conduit, and separated along the periphery of the male manifold adapter water conduit by 180 degrees; 
     wherein the manifold body includes:
         a pair of manifold body air conduits each having a first end configured to connect with an end of a corresponding one of the male manifold adapter air conduits in an air tight manner with a longitudinal axis each manifold body air conduit collinear with the longitudinal axis of the corresponding male manifold adapter air conduit;   a pair of water egress ports each in fluid communication with the manifold body water conduit; and   a pair of air egress ports each in fluid communication with a corresponding one of the manifold body air conduits; and       

     wherein a first one of the water egress ports and a first one of the air egress ports are disposed substantially parallel and adjacent to each other, and are configured to channel respective streams of water and air to a first dual extrusion tube; and a second one of the water egress ports and a second one of the air egress ports are disposed substantially parallel and adjacent to each other, and are configured to channel respective streams of water and air to a second dual extrusion tube. 
     BA5. The supply manifold of paragraph BA4, wherein each of the water egress ports and each of the air egress ports is oriented perpendicular to the first longitudinal axis. 
     C. A hot tub plumbing system, comprising: 
     a manifold configured to receive separate air and water supply streams and to direct those streams into a water egress port and an air egress port, respectively, wherein the water egress port and the air egress port are substantially parallel and adjacent to each other; 
     a flexible dual extrusion tube including a first hollow cylindrical portion configured to couple to the water egress port and a second hollow cylindrical portion configured to couple to the air egress port, wherein the first and second hollow cylindrical portions are joined together at peripheral portions; 
     a jet back including a pair of adjacent parallel hollow protrusions each configured to receive one of the streams of air and water from a respective one of the hollow cylindrical portions of the dual extrusion tube; and 
     a jet body configured to receive the streams of air and water from the jet back, to merge the streams of air and water together to form a mixed stream of air and water, and to provide the mixed stream of air and water from an outlet. 
     C1. The hot tub plumbing system of paragraph C, wherein the jet back includes a central portion configured to create a water tight seal with the jet body, and an attachment mechanism extending from a first end of the central portion and configured to attach the jet back to the jet body in a secure manner. 
     C2. The hot tub plumbing system of paragraph C1, wherein the attachment mechanism includes a pair of opposed, spring-biased clips extending from the first end of the central portion of the jet back, each opposed clip configured to snap into spring-biased engagement with a complementary retaining ridge disposed at a periphery of the jet body. 
     C3. The hot tub plumbing system of paragraph C1, wherein the jet body includes at least one O-ring disposed around a periphery of the jet body, and wherein an inner cylindrical surface of the central portion of the jet back is configured to fit around the O-ring in a substantially water tight compression fit. 
     C4. The hot tub plumbing system of paragraph C, further comprising a jet insert configured fit within an aperture of a hot tub body, to receive the mixed stream of air and water from the jet body outlet, and to channel the mixed stream of air and water into an interior portion of the hot tub body through the aperture. 
     C5. The hot tub plumbing system of paragraph C, further comprising a one-piece clamp configured to hold the dual extrusion tube in water tight engagement with the egress ports of the manifold. 
     C6. The hot tub plumbing system of paragraph C5, wherein the clamp is also configured to hold the dual extrusion tube in water tight engagement with the protrusions of the jet back. 
     C7. The hot tub plumbing system of paragraph C6, wherein the clamp defines a pair of contiguous arcuate apertures and a selectively releasable end portion having first and second sets of complementary ratcheting teeth configured to be engaged with each other upon compression of the end portion. 
     CA. A hot tub plumbing system, comprising: 
     a manifold configured to receive separate air and water supply streams and to channel the streams into a water egress port and an air egress port; 
     a flexible dual extrusion tube including a first tubular portion configured to couple to the water egress port and a second tubular portion configured to couple to the air egress port, wherein the first and second tubular portions are joined together in a figure-eight configuration; and 
     a jet back including a pair of adjacent parallel hollow protrusions each configured to receive one of the streams of air and water from a respective one of the tubular portions of the dual extrusion tube. 
     CA1. The hot tub plumbing system of paragraph CA, further comprising a jet body configured to receive the streams of air and water from the jet back, to merge the streams of air and water together to form a mixed stream of air and water, and to channel the mixed stream of air and water into an outlet. 
     CA2. The hot tub plumbing system of paragraph CA1, further comprising a jet insert configured to be attached within an aperture of a hot tub body, to receive the mixed stream of air and water from the outlet of the jet body, and to channel the mixed stream of air and water into the hot tub through the aperture. 
     D. A method of plumbing a hot tub, comprising: 
     coupling a first end of a flexible dual extrusion tube to a manifold, including coupling a first hollow cylindrical portion of the dual extrusion tube to a water egress port of the manifold and coupling a second hollow cylindrical portion of the dual extrusion tube to an air egress port of the manifold, wherein the water egress port and the air egress port of the manifold are substantially parallel and adjacent to each other; 
     coupling a second end of the dual extrusion tube to a jet back having a pair of adjacent parallel hollow protrusions each configured to couple to a respective one of the hollow cylindrical portions of the dual extrusion tube; and 
     coupling the jet back to a jet body configured to receive streams of air and water from the jet back, to merge the streams of air and water together to form a mixed stream of air and water, and to provide the mixed stream of air and water from an outlet. 
     D1. The method of paragraph D, further comprising coupling the jet body to a jet insert, and inserting the jet insert into an aperture of the hot tub. 
     D2. The method of paragraph D, further comprising coupling separate air and water supply lines to the air ingress port and the water ingress port of the manifold, respectively. 
     D3. The method of paragraph D, wherein coupling the jet back to the jet body includes compressing the jet back against the jet body until a pair of opposed, spring-biased clips extending from a distal end of the jet back snap into spring-biased engagement with a complementary retaining ridge disposed at a periphery of the jet body. 
     D4. The method of paragraph D, wherein coupling the jet back to the jet body includes compressing the jet back against the jet body until four spring-biased clips extending from a distal end of the jet back snap into spring-biased engagement with a complementary retaining ridge disposed at a periphery of the jet body. 
     D5. The method of paragraph D, further comprising clamping the dual extrusion tube to the manifold with a dual aperture clamp defining a pair of contiguous arcuate apertures and a selectively releasable end portion having first and second sets of complementary ratcheting teeth, by compressing the end portion of the clamp until the first and second sets of teeth engage with each other and compress the tube against the egress ports of the manifold. 
     D6. The method of paragraph D, further comprising clamping the dual extrusion tube to the jet back with a dual aperture clamp defining a pair of contiguous arcuate apertures and a selectively releasable end portion having first and second sets of complementary ratcheting teeth, by compressing the end portion of the clamp until the first and second sets of teeth engage with each other and compress the tube against the protrusions of the jet back. 
     DA. A method of plumbing a hot tub, comprising: 
     coupling a first end of a flexible dual extrusion tube to an air egress port and a water egress port of a manifold; 
     coupling a second end of the dual extrusion tube to a jet back having a pair of adjacent parallel hollow protrusions each configured to couple to a respective hollow cylindrical portion of the dual extrusion tube; and 
     DB. A method of plumbing a hot tub, comprising: 
     coupling a first end of a flexible dual extrusion tube to a manifold, including coupling a first hollow cylindrical portion of the dual extrusion tube to a water egress port of the manifold and coupling a second hollow cylindrical portion of the dual extrusion tube to an air egress port of the manifold, wherein the water egress port and the air egress port of the manifold are substantially parallel and adjacent to each other; 
     coupling a second end of the dual extrusion tube to a jet back; 
     coupling an outlet of the jet back to a jet body; 
     coupling the jet body to a jet insert; and 
     attaching the jet insert within an aperture of a hot tub body. 
     E1. A hot tub air and water supply manifold assembly, comprising: 
     a manifold body, including:
         a water ingress conduit having a first end configured to receive water;   a first air ingress conduit having a first end configured to receive air;   a second air ingress conduit having a first end configured to receive air;   a first water egress port in fluid communication with the water ingress conduit;   a second water egress port in fluid communication with the water ingress conduit;   a first air egress port in fluid communication with the first air ingress conduit; and   a second air egress port in fluid communication with the second air ingress conduit;   wherein the water ingress conduit, the first air ingress conduit, and the second air ingress conduit define a first set of parallel longitudinal axes; the first water egress port, the second water egress port, the first air egress port and the second air egress port define a second set of parallel longitudinal axes perpendicular to the first set of parallel longitudinal axes; the first water egress port and the first air egress port are closely separated and configured to couple to a first dual extrusion tube; and the second water egress port and the second air egress port are closely separated and configured to couple to a second dual extrusion tube.       

     E2. The hot tub air and water supply manifold assembly of paragraph E1, further comprising at least two spring biased clips extending from a second end of the water ingress conduit, at least one spring biased clip extending from a second end of the first air ingress conduit, and at least one spring biased clip extending from a second end of the second air ingress conduit. 
     E3. The hot tub air and water supply manifold assembly of paragraph E2, further comprising retaining ridges formed around outer peripheral portions of the first end of the water ingress conduit, the first air ingress conduit, and the second air ingress conduit, wherein the retaining ridges are configured to securely engage spring biased clips extending from an adjacent manifold component. 
     E4. The hot tub air and water supply manifold assembly of paragraph E1, further comprising a male manifold adapter including:
         a male manifold adapter water conduit configured to receive water from a water supply line and to provide water to the first end of the water ingress conduit of the manifold body;   a first male manifold adapter air conduit having a peripheral portion joined to a first peripheral portion of the male manifold adapter water conduit, configured to receive air from a first air supply line and to provide air to the first end of the first air ingress conduit of the manifold body; and   a second male manifold adapter air conduit having a peripheral portion joined to a second peripheral portion of the male manifold adapter water conduit, configured to receive air from a second air supply line and to provide air to the first end of the second air ingress conduit of the manifold body.       

     E5. The hot tub air and water supply manifold assembly of paragraph E1, further comprising a female manifold adapter including:
         a female manifold adapter water conduit configured to receive water from a second end of the water ingress conduit of the manifold body and to provide water to a water supply line;   a first female manifold adapter air conduit configured to receive air from a second end of the first air ingress conduit of the manifold body and to provide air to a first air supply line; and   a second female manifold adapter air conduit configured to receive air from a second end of the second air ingress conduit of the manifold body and to provide air to a second air supply line.       

     E6. The hot tub air and water supply manifold assembly of paragraph E1, further comprising a manifold end cap including a water conduit end cap configured to attach securely to a second end of the water ingress conduit and to prevent passage of water, a first air conduit end cap configured to attach securely to a second end of the first air ingress conduit and to prevent passage of air, and a second air conduit end cap configured to attach securely to a second end of the second air ingress conduit and to prevent passage of air. 
     E7. The hot tub air and water supply manifold assembly of paragraph E1, further comprising a first dual extrusion tube configured to couple to the first water egress port and the first air egress port, and a second dual extrusion tube configured to couple to the first water egress port and the first air egress port. 
     E8. The hot tub air and water supply manifold assembly of paragraph E1, wherein the assembly includes a plurality of substantially identical manifold bodies configured to fit together in a water tight manner, and wherein each of the manifold bodies is configured to emit water and air through a pair of dual extrusion tubes. 
     E9. A hot tub air and water supply manifold, comprising: 
     a water conduit defining a first longitudinal axis and configured to receive water from a water supply line; 
     at least one air conduit defining a second longitudinal axis parallel to the first longitudinal axis and configured to receive air from an air supply line, the air conduit having a periphery joined to a periphery of the water conduit; 
     a first water egress port in fluid communication with the water conduit; 
     a first air egress port in fluid communication with the air conduit; 
     wherein the first water egress port and the first air egress port are disposed substantially parallel and adjacent to each other, and are configured to channel streams of water and air, respectively, to a first dual extrusion tube. 
     E10. The hot tub air and water supply manifold of paragraph E9, wherein the first water egress port and the first air egress port are both oriented substantially perpendicular to the water conduit and to the air conduit. 
     E11. The hot tub air and water supply manifold of paragraph E9, wherein the at least one air conduit includes a first air conduit joined to a first portion of the periphery of the water conduit, and a second air conduit joined to a second portion of the periphery of the water conduit, wherein the first air egress port is in fluid communication with the first air conduit, and further comprising: 
     a second water egress port in fluid communication with the water conduit; 
     a second air egress port in fluid communication with the second air conduit; 
     wherein the second water egress port and the second air egress port are disposed substantially parallel and adjacent to each other and are configured to channel streams of water and air, respectively, to a second dual extrusion tube. 
     E12. The hot tub air and water supply manifold of paragraph E11, wherein the first portion of the periphery of the water conduit and the second portion of the periphery of the water conduit are separated from each other by approximately 180 degrees. 
     E13. The hot tub air and water supply manifold of paragraph E11, further comprising a first spring-biased clip extending from a peripheral portion of a distal end of the first air conduit and a second spring-biased clip extending from a peripheral portion of a distal end of the second air conduit, and wherein the first and second spring-biased clips are respectively configured to engage complementary retaining ridges disposed at peripheral portions of first and second air conduits of an adjacent air and water supply manifold. 
     E14. The hot tub air and water supply manifold of paragraph E11, further comprising a first retaining ridge disposed at a peripheral portion of the first air conduit and a second retaining ridge disposed at a peripheral portion of the second air conduit, wherein the first retaining ridge is configured to engage securely with a spring-biased clip extending from a first air conduit of an adjacent air and water supply manifold, and the second retaining ridge is configured to engage securely with a spring-biased clip extending from a second air conduit of the adjacent air and water supply manifold. 
     E15. A hot tub air and water supply manifold system, comprising: 
     a male manifold adapter, including:
         a male manifold adapter water conduit defining a first longitudinal axis and configured to receive water from a water supply pipe; and   a first male manifold adapter air conduit defining a second longitudinal axis parallel to the first longitudinal axis, the first male manifold adapter air conduit having a periphery joined to a periphery of the male manifold adapter water conduit;       

     a manifold body, including:
         a manifold body water conduit having a first end configured to connect with one end of the male manifold adapter water conduit in a water tight manner with a longitudinal axis of the manifold body water conduit collinear with the first longitudinal axis;   a first manifold body air conduit having a first end configured to connect with one end of the first male manifold adapter air conduit in an air tight manner with a longitudinal axis of the first manifold body air conduit collinear with the second longitudinal axis;   a first water egress port in fluid communication with the manifold body water conduit; and   a first air egress port in fluid communication with the first manifold body air conduit;       

     wherein the first water egress port and the first air egress port are disposed substantially parallel to each other, and are configured to channel respective streams of water and air to a first dual extrusion tube. 
     E16. The hot tub air and water supply manifold system of paragraph E15, further comprising an end cap including a water conduit end cap configured to attach securely to a second end of the manifold body water conduit and to prevent passage of water, and a first air conduit end cap configured to attach securely to a second end of the first manifold body air conduit and to prevent passage of air. 
     E17. The hot tub air and water supply manifold system of paragraph E15, wherein the first water egress port and the first air egress port are each oriented perpendicular to the first longitudinal axis. 
     E18. The hot tub air and water supply manifold system of paragraph E15, wherein the male manifold adapter includes:
         a second male manifold adapter air conduit defining a third longitudinal axis parallel to the first and second longitudinal axes, the second male manifold adapter air conduit having a periphery joined to the periphery of the male manifold adapter water conduit; and       

     wherein the manifold body includes:
         a second manifold body air conduit having a first end configured to connect with one end of the second male manifold adapter air conduit in an air tight manner with a longitudinal axis of the second manifold body air conduit collinear with the third longitudinal axis;   a second water egress port in fluid communication with the manifold body water conduit; and   a second air egress port in fluid communication with the second manifold body air conduit;       

     wherein the second water egress port and the second air egress port are disposed substantially parallel to each other, and are configured to channel respective streams of water and air to a second dual extrusion tube. 
     E19. The hot tub air and water supply manifold system of paragraph E15, wherein the male manifold adapter includes a pair of male manifold adapter air conduits, each defining a separate longitudinal axis parallel to the first longitudinal axis, each having a periphery joined to a periphery of the male manifold adapter water conduit, and separated along the periphery of the male manifold adapter water conduit by 180 degrees; 
     wherein the manifold body includes:
         a pair of manifold body air conduits each having a first end configured to connect with an end of a corresponding one of the male manifold adapter air conduits in an air tight manner with a longitudinal axis each manifold body air conduit collinear with the longitudinal axis of the corresponding male manifold adapter air conduit;   a pair of water egress ports each in fluid communication with the manifold body water conduit; and   a pair of air egress ports each in fluid communication with a corresponding one of the manifold body air conduits; and       

     wherein a first one of the water egress ports and a first one of the air egress ports are disposed substantially parallel and adjacent to each other, and are configured to channel respective streams of water and air to a first dual extrusion tube; and a second one of the water egress ports and a second one of the air egress ports are disposed substantially parallel and adjacent to each other, and are configured to channel respective streams of water and air to a second dual extrusion tube. 
     E20. The hot tub air and water supply manifold system of paragraph E19, wherein each of the water egress ports and each of the air egress ports is oriented perpendicular to the first longitudinal axis. 
     F0. A hot tub jet assembly comprising: 
     a jet back including a first hollow protrusion configured to receive a stream of water and a second hollow protrusion adjacent the first hollow protrusion and configured to receive a stream of air; 
     a jet body configured to receive the streams of water and air from the jet back, to merge the streams of water and air together to form a mixed stream of air and water, and to provide the mixed stream of air and water from an outlet; 
     wherein the jet back includes a resilient ring configured to engage one or more hooks disposed on the jet body. 
     F1. The hot tub jet assembly of paragraph F0, wherein each of the one or more hooks comprises a tapered projection extending radially from the jet body. 
     F2. The hot tub jet assembly of any one of paragraphs F0 through F1, wherein the resilient ring is integral with the jet back. 
     F3. The hot tub jet assembly of any one of paragraphs F0 through F2, wherein the first and second hollow protrusions extend substantially parallel to a longitudinal axis of the jet back. 
     F4. The hot tub jet assembly of any one of paragraphs F0 through F3, further comprising a jet insert configured to fit within an aperture of a hot tub body, to receive the mixed stream of air and water from the jet body outlet, and to channel the mixed stream of air and water into an interior portion of the hot tub body through the aperture. 
     F5. The hot tub jet assembly of paragraph F4, wherein the jet body includes a threaded interior wall portion configured to threadedly receive the jet insert. 
     F6. The hot tub jet assembly of paragraph F5, wherein the jet body has a first diameter at the threaded interior wall portion and a second diameter at a downstream portion, and the first diameter is smaller than the second diameter. 
     F7. The hot tub jet assembly of any one of paragraphs F5 through F6, wherein a flange is disposed at a downstream end of the jet body, the flange has a circumferential channel, and the channel includes a plurality of molded ribs configured to engage the jet insert, thereby preventing the jet insert from disengaging from the threaded interior wall portion. 
     G0. A hot tub plumbing system comprising: 
     a manifold assembly configured to receive separate air and water supply streams and to direct the streams into a water egress port and an air egress port, wherein the air egress port is substantially parallel to and adjacent to the water egress port; 
     a dual extrusion tube including a first tubular portion configured to couple to the water egress port and a second tubular portion configured to couple to the air egress port; 
     a jet back including a pair of adjacent parallel hollow protrusions each configured to receive one of the streams of air and water from a respective one of the tubular portions of the dual extrusion tube; and 
     a jet body configured to receive the streams of air and water from the jet back, to merge the streams of air and water together to form a mixed stream of air and water, and to provide the mixed stream of air and water from an outlet; 
     wherein the jet back includes a resilient member extending from a first end of the jet back and configured to engage one or more projections extending from the jet body. 
     G1. The hot tub plumbing system of paragraph G0, wherein the resilient member comprises a resilient ring spaced from the first end of the jet back by one or more openings, and the resilient ring is configured to retain the one or more projections within the one or more openings. 
     G2. The hot tub plumbing system of paragraph G1, wherein the one or more projections extending from the jet body each have a sloped surface configured to slidingly engage a complementary sloped lip of the resilient ring, thereby facilitating insertion of the jet body into the jet back. 
     G3. The hot tub plumbing system of any one of paragraphs G0 through G2, wherein at least a portion of an interior of the jet body is configured to threadedly receive a jet face. 
     G4. The hot tub plumbing system of any one of paragraphs G0 through G2, wherein the jet body further includes a grooved flange, and the grooved flange includes a plurality of stops configured to prevent rotation of a jet face engaging the flange. 
     G5. The hot tub plumbing system of any one of paragraphs G0 through G4, further comprising a first monolithic clamp configured to hold the dual extrusion tube in water-tight engagement with the egress ports of the manifold assembly. 
     G6. The hot tub plumbing system of paragraph G4, further comprising a second monolithic clamp configured to hold the dual extrusion tube in water-tight engagement with the hollow protrusions of the jet back. 
     H0. A hot tub plumbing system comprising: 
     a manifold configured to channel an air stream into an air egress port and to channel a water stream into a water egress port; 
     a dual extrusion tube including a first hollow portion configured to couple to the water egress port and a second hollow portion configured to couple to the air egress port; and 
     a jet back including:
         a first hollow protrusion configured to receive the water stream from the first hollow portion of the dual extrusion tube;   a second hollow protrusion configured to receive the air stream from the second hollow portion of the dual extrusion tube; and   a spring-biased ring spaced from a first end of the jet back.       

     H1. The hot tub plumbing system of paragraph H0, further comprising a jet body including one or more retaining surfaces configured to engage the spring-biased ring, thereby retaining the jet body at least partially within the jet back. 
     H2. The hot tub plumbing system of paragraph H1, further comprising a jet insert, and wherein the jet body includes a threaded portion configured to threadedly engage the jet insert and a circumferential channel including a plurality of ribs configured to inhibit the jet insert from screwing out of the threaded portion of the jet body. 
     H3. The hot tub plumbing system of any one of paragraphs H0 through H2, wherein the first and second hollow protrusions of the jet back extend in a direction transverse to a longitudinal axis of the jet back. 
     H4. The hot tub plumbing system of any one of paragraphs H0 through H3, wherein the first and second hollow portions of the dual extrusion tube are flexible and are joined together in a figure-eight configuration. 
     Advantages, Features, Benefits 
     The different embodiments and examples of the hot tub plumbing system, its components, and its methods of installation described herein provide several advantages over known solutions for delivering air and water to hot tub jets and for efficiently assembling a plumbing system. 
     For example, illustrative embodiments and examples described herein reduce the amount of labor during hot tub assembly by significantly decreasing the number of tubes, connections and associated fittings used. This decrease is accomplished by using dual extrusion tubing which delivers air and water simultaneously. Benefits of using dual extrusion tubing may include significantly reducing (for example, by 50%) the amount of labor involved in installing the plumbing system in a hot tub, as well as decreasing the likelihood of mistakes in the tube routing. Furthermore, dual extrusion tubing can be used in conjunction with specialized manifolds, described herein, which simplify how air and water are routed to the hot tub jets. 
     Additionally, the systems and methods of installing a plumbing system according to the present teachings may simplify installation by using a “press-and-click” assembly. Benefits of this method of assembly may include a further reduction in labor, as well as a reduction in the amount of glue and adhesive used. The reduction or elimination of glue and primer is significant for several reasons. For example, manual application can be inconsistent, which can lead to failures of the joint that are difficult and costly to repair. Furthermore, glue and primer contain volatile organic compounds that can pose environmental and human health issues. 
     No known system or device can provide the advantages described above, among others. However, not all embodiments and examples described herein provide the same advantages or the same degree of advantage. 
     CONCLUSION 
     The disclosure set forth above may encompass multiple distinct examples with independent utility. Although each of these has been disclosed in its preferred form(s), the specific embodiments thereof as disclosed and illustrated herein are not to be considered in a limiting sense, because numerous variations are possible. To the extent that section headings are used within this disclosure, such headings are for organizational purposes only. The subject matter of the disclosure includes all novel and nonobvious combinations and subcombinations of the various elements, features, functions, and/or properties disclosed herein. The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. Other combinations and subcombinations of features, functions, elements, and/or properties may be claimed in applications claiming priority from this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.