This lead free CrimpRing (TM) adapter is used to make a straight transition between copper pipe and potable or radiant heating PEX tubing. This 1 crimp c 3/4 inch male threaded adapter is made of lead free poly alloy and must be joined to the PEX tubing using a copper crimp ring to form a fast, reliable, and permanent seal. It is recommended to use an electric crimp tool to make the crimp connection.