The Cello WP7-24 is specifically designed to connect various sizes and lengths of copper tubing and other copper parts together and direct the movement of water or gas depending on the application. This fitting is equipped with sweat (non-threaded) connections and requires copper flux (a liquid cleaning agent), and solder to create a leak-proof and permanent connection. Note: For best copper solder connection, use open mesh or emery cleaning cloth to clean the inside of the fitting and outside of the pipe. The Cello WP7-24 is designed to be used in a wide variety of potable water applications. This fitting offers you quality and delivers top value in commercial, industrial and residential applications. When installing the Cello WP7-24, be sure to keep the fitting and pipe clear of debris and protect yourself from the heat being applied for soldering. This elbow is pressure tested before leaving the factory.