This is a high-quality high-power SCR voltage regulator with stepless control, designed to adjust speed, temperature, voltage, and light. It features a high-temperature resistant FR-4 circuit board, imported SCR chip, full aluminum heat sink, precision resistors, and high-voltage capacitor. Equipped with a separate switch for independent control of input power, enabling easy power on/off operation. Features a peak voltage absorption circuit for immediate response with no delay, effectively protecting the high-power SCR. Offers surge protection, spike suppression, RC absorption, and multiple safety protections. The flame-retardant insulated enclosure is heat-resistant, rustproof, pressure-resistant, and durable. Includes industrial-grade sockets with thickened copper contacts for reliable connection and safety. Designed with mounting holes for flexible installation on flat surfaces or hanging positions. Operates silently, energy-efficient, with stable noise resistance and wide application range. Suitable for use with electrical devices such as electric stoves, water heaters, heat lamps, small motors, soldering irons, and more.Note: When measuring output voltage without a load, the reading may be inaccurate. A minimum 20W load is required for correct voltage measurement. Input is AC and output is AC, not DC. The 4000W rating applies to resistive loads only. Inductive loads should not exceed one-third of the rated resistive load capacity. Resistive loads include incandescent lamps and heating elements; inductive loads include series-wound motors. Use caution when connecting sensitive electronic devices. This product has a metal case and must be properly grounded for safe operation.Specifications: Name: SCR Voltage Regulator Model: NHT-4000W Material: Aluminum Color: Black Input Voltage: AC 220V Output Voltage: 0-220V Max Power: 4000W Voltage Adjustment Range: 0-220V Rated Current: 9A Max Current: 18A Main Unit Dimensions: 115 x 100 x 83mm (4.53 x 3.94 x 3.27in) Item Weight: 459g (1.01lb) Package Dimensions: 180 x 100 x 115mm (7.09 x 3.94 x 4.53in) Package Weight: 522g (1.15lb) Package List: 1 x SCR Voltage Regulator