Made of a high-performance plastic fitting product called polysulfone, the highly rated Watts AquaLock End Cap, P-670 is designed for years of trouble-free use. Among the easiest tools on the market for joining copper, polybutylene, CPVC and PEX (LDPE, MDPE, HDPE) tubing, it features a ½-inch copper tube size quick connect and 7/8- inch ballcock. Its patented O-ring guide ensures zero-leak connections by correctly aligning tubing, protecting the O-ring from damage and boosting side load capacity. A locking clip offers extra security. Install by simply cutting pox, copper or cpvc pipe and inserting into the fitting to the tube stop; disconnect by pulling back on the ring. Holds up to 250 psi. Code-approved for behind-wall-without-access and direct-in-ground burial installations; nsf-14, nsf-61, CSA/astm & upc code listed and approved. Excellent replacement for quest and flare-it type fittings. Made in ChinIncludes 25-year limited warranty.From the manufacturer:Unlike barb fittings, this product joins tubing on the outside to boost flow capacity. The corrosion-resistant stainless steel gripping teeth in the collets allow for close interlocking with multiple materials. The tube swivels when connection takes place under maximum pressure, making this product ideal for vibrating and dynamic applications.