Lincoln Air Coupler is 1/4" NPT(f) inlet, 250 psi maximum operating Pressure. Extra long stem of Nipple and Coupler Body insures long service life, easy connections under severe operating conditions. Maximum air flow is 52 SCFM at 100 psi. Length is 2-1/2", diameter 1-1/16" and weighs 4-1/2 ounces.