page_title: Diving cylinder
section_title: Cylinder thread variations
hierarchical_section_title: Diving cylinder / Parts / The cylinder valve / Cylinder thread variations
caption_attribution_description: English: Dräger cylinder valve with taper thread for 300 bar service
context_page_description: A diving cylinder, scuba tank or diving tank is a gas cylinder used to store and transport the high pressure breathing gas required by a scuba set. It may also be used for surface-supplied diving or as decompression gas or an emergency gas supply for surface supplied diving or scuba. Cylinders provide gas to the diver through the demand valve of a diving regulator or the breathing loop of a diving rebreather.
  Diving cylinders are usually manufactured from aluminium or steel alloys, and are normally fitted with one of two common types of cylinder valve for filling and connection to the regulator. Other accessories such as manifolds, cylinder bands, protective nets and boots and carrying handles may be provided. Various configurations of harness may be used to carry the cylinder or cylinders while diving, depending on the application. Cylinders used for scuba typically have an internal volume of between 3 and 18 litres and a maximum working pressure rating from 184 to 300 bars.
context_section_description: Cylinder threads may be in two basic configurations: Taper thread and parallel thread. These thread specifications are detailed in a previous section. The valve thread specification must exactly match the neck thread specification of the cylinder. Improperly matched neck threads can fail under pressure and can have fatal consequences.
  Parallel threads are more tolerant of repeated removal and refitting of the valve for inspection and testing.
caption: Draeger 300 bar taper thread DIN cylinder valve
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