Air Valve, 1/8" Vent-Rite #1 Eliminates Air Steam Venting Air Valve It will open and close all pressures up to 3 P.S.I. Do not use at system pressure above 10 P.S.I. This air valve is easily installed its standard 1/8 male connection Vent Port: 3/32". Operating Pressure: 3 psi