High Quality: Uses high-performance SCR as internal chip. Thickened metal shell, heat-resistant and durable.Perfect Performance: Stepless voltage adjustment with rotary knob, zero hysteresis, zero delay, fast response.The AC voltage regulator cover includes a universal multi-purpose socket and current display. Provides multiple protection features to effectively safeguard high-performance thyristors against overvoltage and voltage limits.Note 1: The 4000W refers to maximum power under resistive loads. Power under inductive loads is one-third of that under resistive loads. Resistive loads include incandescent lamps, heating elements, and similar devices. Use caution when operating electronic products with circuit boards.Note 2: The output voltage reading is not accurate without a load. A load of at least 20W is required to measure correct output voltage. The output is AC with a metal shell and must be properly grounded.Product Specification:Model: BTA-4000WInput Voltage: AC 220VPlug Type: EU PlugOutput Voltage: 0-220V continuously adjustable (voltmeter may not function accurately below 5V)Power Rating: Up to 3000W for resistive loadsRated Current: 9ACurrent Limit: 18APackage Weight: Approx. 507gPackage List:1 x Speed Controller 220V