High Quality: Use high performance SCR as internal chip.Thickening metal shell, high temperature resistant and durable in use.Leistung Perfect Performance: Stepless voltage adjustment with rotary knob, zero hysteresis, zero delay, fast response.The AC voltage regulator cover is equipped with universal multi-purpose socket and current display.Effectively protect high-performance thyristors against overvoltage and voltage limits with multiple protection Note 1: The 4000W mentioned above refers to the maximum power when working under resistive loads.Power under inductive load is 1/3 of resistive load.The resistive load concerns Wolframlampt Diew.on line excitation motor and more.Electronic products with circuit boards should be used with caution.Note 2: The measured output voltage is a virtual voltage if there is no load.It must be connected to a load of 20W or more to measure the correct output voltage.The output is a Wehtselstrom metal shell and must be safely grounded.