This air admittance valve can be used as an individual, branch, circuit, or stack vent. It allows air to enter DWV systems to equalize pressure when water drains out of the system. Item: Air Admittance Valve Product Group - Drains: Air Valves and Vents Pipe Dia. - Drains: 3" to 4" Material of Construction - Drains: ABS Color - Drains: White Connection - Drains: Slip For Use With: Venting Single Fixture, Individual Branch, Circuit Vent Or Stack Type Application Up To 500 DFU Length (In.): 5-1/4 Standards: ASSE Performance Standard 10510 And 1051, NES-592, NSF Standard 14, IAPMO, File No C-3803, ITS Intertek Testing Services Package Quantity: 1