Georg Fischer. Primofit. Transition piece for steel with straight external screw thread. The fittings made of malleable cast iron are available in a black and thermally galvanised version. Due to the durable character of these fittings and the high mechanical stress and temperature resistance, these fittings are frequently used. The screw thread is a universal, EN 10226-1 standardised connection that guarantees safe use in a wide range of applications. In addition to the threaded fittings, a compression fitting made of malleable cast iron is available. This fitting, sold under the brand name PRIMOFIT, is available in a black and thermally galvanised version. It offers a time-saving connection of steel, PE, lead and butt-welded steel pipes.