2PCS Pneumatic Check Valve, 12mm Inner Dia Straight One-Way Valve with Push to Connect Quick Connector for Air Compressor and Vacuum Pump Systems

{One-Way Flow Protection} The check valve is designed to allow flow in only one direction, automatically closing and sealing when pressure reverses. Prevents backflow of compressed air, vacuum, or fluid into sensitive components. The built-in spring-assisted valve core responds quickly to flow changes, closing immediately when forward pressure drops. {Size Options} Available in three inner diameters: 8mm, 10mm, and 12mm, allowing you to choose the precise size for your tubing and flow requirements. 8mm suits small-bore pilot lines and instruments; 10mm fits standard industrial pneumatic lines; 12mm handles higher flow for main supply lines and vacuum systems. {Dual-Material Construction} Made of corrosion-resistant nickel-plated brass, while internal components and the collet are made of high-strength PBT. The hybrid construction combines the durability and pressure rating of metal with the low friction and sealing properties of advanced polymer. The result is a valve that withstands moisture, oil mist, and temperature changes without sticking or leaking. {Push-In Installation} The push-in fitting design allows instant tube connection without tools, clamps, or sealant. Insert the tube into the collet until it bottoms out, and the internal stainless steel gripping ring locks it securely. To disconnect, press the collet and pull the tube out. {Multi-Scenario Application} Used in gas equipment, CNC machines, air lines, pneumatic tools, automatic assembly lines, and other industrial equipment. Suitable for hoses, PU tubing, and nylon tubing.