http://www.ka-valve.com/check-....valve/different-size China Different Size Check Valve Product Description The 1 inch check valve opening and closing parts are opened or closed by themselves by the flow and force of the medium to prevent the backflow of the medium. The valve is also called a 25mm check valve, 1 inch one way valve. The check valve belongs to the automatic valve category, which is mainly used in the pipeline where the medium flows in one direction, and only allows the medium to flow in one direction to prevent accidents. 1 inch check valve type Check valves include lift check valve, swing check val