Qosina offers an extensive line of Check Valves, available in a variety of styles that are in stock and ready for immediate delivery. Qosina part # 80393 features a clear, 0.138 inch OD tubing port inlet and a blue, 0.138 inch OD tubing port outlet. Made of polycarbonate and silicone, this in-line valve and has a low, 0.25 psi cracking pressure, determining when the component starts to open and can withstand 45 psi of back pressure. Qosina offers a variety of flow rates, materials, cracking pressure and back pressure options. Check Valve sample kits are also available which are ideal for testing.