Netafim Techflow Pressure Compensating Emitter with Nipple Outlet, 2 GPH - Green - Pack of 250 (WPC20-250)Techflow Emitter The unique design of the Netafim Techflow Emitters regulates flow and provides continuous self cleaning action during operation. These emitters have a 2. 2 PSI internal check valve that helps prevent low emitter drainage holding back up to a 5 ft column of water. The anti siphon operation prevents contaminants from being drawn into the emitter. The Techflow Emitters are pressure compensating and deliver the same flow from 14. 5 to 58