NDS 420C Pop-Up Drainage Emitter, 3 4-Inch, Green NDS POP-UP DRAINAGE EMITTERS: Acts as the discharge point of a drainage system. The pop-up emitter is opened by the hydrostatic pressure of water flowing through the drain pipe and as flow diminishes the emitter closes POP-UP TOP ADVANTAGE: This will keep rodents and debris out of the system, and reduces a trip hazard posed by open drains SAVE EARTH AND SAVE HOME: Manufactured from 100% recycled HDPE. NDS Pop-Up Drainage allows water to be diverted and released to water-safe areas away from structures, erosion-prone landscapes, and poor drainage areas NDS DRAINAGE EMITTER FITTINGS: The NDS pop-up drainage emitter is an easy, safe, and efficient solution to any drainage needs AVAILBILE SIZE: NDS Pop up Drainage Emitter is available in Dimension(s): 1-1/4" H. Diameter: 5-15/16"; inner diameter: 3-7/16". It fits 3-inch and 4-inch hub sewer and drain fittings