The tube cap features a solder cup. The fitting is used to fit over the end of pipe to seal the end. In addition to its inherent qualities of beauty, durability and low maintenance, coppers reusability makes it an ideal application in sustainable projects. Nibco® copper fittings are manufactured in an ISO 9001 certified facility, and backed by a 50 years limited warranty. Because of its longstanding reputation for innovation and precision in design and manufacturing, Nibco® is the preferred brand in the industry.