With screw type terminal blocks, the inserted wire is fixed by means of a screw and thus contacted as well.The clamping bodies consist of a wrought copper alloy. The surface is galvanically plated with nickel. For types with soldering pin, the surface is galvanically underlaid with nickel and then plated with tin in order to achieve a high level of corrosion resistance and excellent solderability. All clamping bodies are undetachably fitted into the insulation housing.The terminal screws from M2 to M4 are manufactured alternatively in different materials. (The screws are rounded on the thrust faces, which permits connecting the conductor even without wire protection.)Normally, the screws are secured against coming loose by themselves.Contact systemsa) lamella contactsThe lamella contacts are silver-plated, alternatively tin-plated or gold-plated, and are suited for round pins. Due to the lamella-type contact bridges, currents of up to 10 A may be transmitted. Even after making the connection for a hundred times, the transition resistance between the socket contact and the multi-pin connector is less than or equal to 5 milliohms. b) plug-in systems with integrated contactThe tulip-shaped plug-in system is made of bronze and is suited for round and square pins.Positively driven wire protectionSome types are equipped with a positively driven wire protection which works according to the lift system. When the screw is turned, the wire protection moves in parallel to the clamping body base.Lift systemDue to the elevator effect of the clamping body, the conductor is clamped extensively and in parallel. Damage to the conductor caused by the screw is totally excluded in this case as well.