Check Valve, In Line, Inlet (In.) 1/2 in (F)NPT, Outlet (In.) 1/2 in (F)NPT, Brass, Hold Back Pressure (PSI) 450 psi, Max. Pressure (PSI) 450 psi, Cracking Pressure (PSI) 0.1 psi, Hex Size (In.) 1 1/4 in, Flow Range Free Air (CFM) 0 to 20 cfm, Max. Temp. (F) 400 Degrees F, Vertical or Horizontal Mounting, Tap Size 1/8 in for Pressure Switch Unloader Connection, Length (In.) 2 7/8 in, Stainless Steel Spring Material, PTFE Poppet, In-Line Check Valve WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov - Nickel (Metallic)