Marketing InformationThe Ring Check valve''''s design has 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). As an addition to the NIBCO Press System, the press end connections make the Ring Check quick and easy to install. he.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.