Oatey Sure-Vent 1-1/2 in. PVC Air Admittance Valve with 20 DFU Branch and 8 DFU Stack (2-Pack)

Oatey's Air Admittance Valve is a 1-way valve designed to allow air to enter the plumbing drainage system when negative pressure develops in the piping system. The device will close by gravity and seal the vent terminal under zero differential pressure (no flow conditions) and under positive internal pressures. This plumbing AAV also prevents sewer gases from escaping into the building.Pack includes two air admittance valvesOffers unmatched breathing capability with a unique sealing systemFor use as a secondary ventCloses by gravityComplies to ASSE standard 1050 and 10511-size approved to handle up to 2 in. vent pipe