Check valves prevent backflow by automatically closing when fluid reverses direction. Wafer checks may be installed in horizontal positions (or vertical with flow moving up). Please refer to NIBCO technical data sheets, chemical resistance guides and catalogs for engineering and installation information. Choose NIBCO® check valves for the most specified, versatile and economical valve option in commercial, mechanical and industrial applications. NIBCO® check valves are backed by the NIBCO 5-moreyear 125% limited warranty. less