Feature: 1. Compared with similar check valve spool, it can be used for a longer time with manufactured by new technology. 2. It is an excellent substitute for old or damaged check valve core of air compressors. 3. The spring check valve is suitable for cylinder heads of oil‑ machines and air compressors. 4. The spring check valve is made of rubber so it is durable, safe and has a long service life. 5. Preventing process from reversing, it is a mechanical valves that permit liquids to in only . Specification: Item Type: Spring Check Valve Material: Rubber Package List: 10 x Rubber Stopper 10 x Spring Note: Before replacing the spool, make sure that the compressors are completely closed and the pressure is completely relieved.