Oatey® Sure-Vent® Air Admittance Valve, 3 x 4 in Nominal, NPT, -40 to 150 deg F, 500 dfu, 2.92 in Inlet to Outlet Length, ABS Body, 7.23 in H
Oatey® Sure-Vent® 500 DFU Capacity Air Admittance Valve's one-way valve is designed to allow air to enter the plumbing drainage system when negative pressures develop in the piping system.