The NIBCO Press System EPDM O-ring seal is an essential part of the press system design. Simply applying pressure from a pressing tool tightens the O-ring onto the tube, ensuring a clean, watertight seal in seconds with no flame, solder or flux. The EPDM seal must be checked and in place, before a fitting or valve end is pressed. The seal must be replaced if it becomes contaminated or loose. The seal should not be lubricated with anything other than water. Fluids containing hydrocarbons are not compatible with the EPDM seal. NIBCO Press System fittings are the fastest, easiest way to join copper tubing systems in residential and commercial potable, hot, chilled and process water applications for plumbing and HVAC systems. The press fittings can also be installed underground. 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 and copper alloy fittings, commercial valves, accessories, pressing tools, jaws and chains. In addition to its inherent qualities of beauty, durability and low maintenance, copper's reusability makes it an ideal application in sustainable projects. NIBCO Press System copper fittings are backed by a 50-year limited warranty. Because of its longstanding reputation for innovation and precision in design and manufacturing, NIBCO is the preferred brand in the industry.