Features Advanced Material: This one-way air check valve is made of high-quality stainless steel material, with stable performance, not easy to corrode and rust, good air tightness and long service life. Tight and Non-slip: The air check valve adopts precision BSPP internal thread, which is convenient to connect, does not slip, is not easy to fall off, and has good reliability. Easy Installation: The hexagonal female thread air check valve is easy to install and disassemble, and the old or damaged ones can be directly replaced, saving your energy and time. Four Sizes: There are 4 sizes of air check valves to choose from: 1/8", 1/4", 3/8", 1/2", to meet your various usage needs. Application: This air check valve is very suitable for pipeline connection under gas, water, oil and other media. Specification: Condition: Brand new Material: 304 Stainless steel Thread: BSPP female thread Optional Style: 1/8in, 1/4in, 3/8in, 1/2in   Package List: 1 x Air Check Valve Package List