Hex one-way check valve is made of high quality stainless steel 304 material, which is robust, rust-proof, high pressure resistant and corrosion resistant. The valve is a one-way flow, pay attention to the fluid direction and the valve's import and export direction when installing (the valve body has arrow markings) to achieve no backflow. The valve body not removable and can still maintain sealing, performance under high pressure. The standard NPT female thread can be match with other NPT male thread fittings. This air check valve can be used for one-way transmission of gas, water, oil, and other media. The hexagonal design is easy install and remove.