SODIAL(R) 4 Pcs 3mm Inside Diameter Hard Plastic One-way Check Valve Dark Blue Product Name: One-way Valve Flow Medium: Air, Liquid Main Material: Hard Plastic; Color: Dark Blue Length: 36 mm/ 1.4"; Connector Diameter: 4mm/ 0.16"; External Diameter: 19mm/ 0.7" Package: 4 x Quick Exhaust Valve