H71 Stainless Steel Wafer Type Non Return Check Valve Wafer type check valve, has single disc type and double disc type, but all type open and close automatically by spring. So check valve are also named as one way valve, spring return valve, or non-return valve. Check valve has swing type and vertical type, but generally speaking, wafer type check valve could install both in horizontal and vertical direction. Single disc wafer type check valve, it has a spring in it to control the disc. When fluid come, it will give pressure to spring to control open and close. So spring is a very important part in a valve. Specifications: Product Name Single Disc Wafer Check Valve 2~24 inches 1. Material SS304/316/304L/316L ( CF8/CF8M/CF3/CF3M), WCB, WCC, LCB,LCC,WC6,WC9, C5,C12, etc…