The Viper 2500S is a unique, compact TIG control unit that independently controls the welding current of any DC power source without the need for auxiliary or control cables. It operates from the open circuit voltage of any DC power source with an output of 40-100 V (petrol or diesel generators, rectifiers, inverters, etc.), can be used with one or two-piece torches, and provides excellent MMA and TIG welding characteristics.