The NIBCO Ring Check valve is designed with an in-line, spring assisted self-closing disc. The two-piece valve features a stainless steel stem and resilient PTFE disc. The valve is recommended for domestic hot and cold water, HVAC (condensers, chilled water, hot water heating). The NIBCO Press System is user friendly, quick and easy to install. When properly crimped a unique ''''N'''' witness mark is clearly visible. Please refer to NIBCO technical data sheets and catalogs for engineering and installation information. NIBCO Press System applies the proven performance of press technology to NIBCO valves and fittings -- the most specified flow control products in the industry. The NIBCO Press System features a full range of precision engineered copper fittings, bronze valves, accessories, pressing tools, jaws and chains. NIBCO Press System valves are backed by a 5-year limited warranty. Because of its longstanding reputation for innovation and precision in design and manufacturing, NIBCO is the preferred brand in the industry.