Check Valve, In Line, Inlet (In.) 1/4 in (F)NPT, Outlet (In.) 1/4 in (F)NPT, Brass, Hold Back Pressure (PSI) 400 psi, Max. Pressure (PSI) 450 psi, Cracking Pressure (PSI) Less than 3, Hex Size (In.) 13/16 in, Flow Range Free Air (CFM) 0 to 12 cfm, Max. Temp. (F) 400 Degrees F, Vertical or Horizontal Mounting, Tap Size -, Length (In.) 2 1/8 in, Stainless Steel Spring Material, Disc Positive Seating Fluoropolymer, for Maximum Air Flow, PTFE Poppet, Thread Coating -, - Seal, In-Line Check Valve WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov - Nickel (Metallic)