ProLock end caps from John Guest USA are available in 3/8- to 1-inch CTS sizes. They can act as emergency water stoppers and can also be used for pressure testing rough-ins and temporary cap-off installations. They are manufactured from engineered plastic and are UV-resistant outdoors. Suitable to use with copper, PEX or CPVC pipe, they require no tools to make secure, lead-proof connections. 973/808-5600; www.johnguest.com.