A self-cleaning, lead free soldering flux in a paste form specially formulated for sweat fitting work. No surface preparation is needed. Copper-Mate removes oxidation and prepares copper, lead, brass, tin, stainless steel, cast and wrought iron (except aluminum) for the proper bonding of solder to metal assuring leak tight joints. It makes the solder flow freely and tin perfectly. It won't burn, char or spatter. It is recommended for all soft solder work and for potable water. Contains no lead or solder. Great for all diameter pipe.