2" ProPress Copper Union. Hard Copper Pipe is generally used for supply of hot and cold water in both commercial and residential applications. Rigid or hard copper is always soldered, crimped, or pressed as the form of connection. Copper offers a high level of resistance to corrosion, and needs fittings to get around bends and obstacles. Copper fittings also range in application. ProPress Fittings require only a smooth and clean connection area for the best press. ProPress is much faster than the general heat applications. This 2" ProPress Copper Union is designed to connect two existing copper lines. This union features a threaded ring that is tightened to connect the two pressed fittings. Great for line repairs.