Total length: 36mm / 1.42in, the middle circle diameter: 8mm / 0.31in Both ends: inner diameter: 3mm / 0.12in, outer diameter: 4mm / 0.16in Suitable for common air hose (innner diameter approx. 4mm / 0.16in) Note: The OUT surface is air outlset, and the other side is the air inlet. Package included: 5PC Valves