Item Type: AC Voltage Regulator Material: Cold rolled steel, aluminum alloy, thyristor, PCB Uses: High-power thyristor voltage regulation, speed regulation, temperature regulation, and dimming applications. Suitable for household appliances, industrial electrical appliances, scientific test equipment, and electrical equipment for factories, schools, etc. Item Parameters Output voltage: 0-220V adjustable (Voltmeter does not function when output voltage is below 5V) Limit power: 4000W (compatible with 2000W-3000W resistive load) Regulating range: 0-220V continuously adjustable under load; step-down to 0V, step-up to 10V Rated current: 9A Limit current: 18A Overload protection: Yes Thyristor model: STMicroelectronics BTA41-600B/800B Size: Approx. 5.3cm x 10cm x 8.4cm (2.1in x 3.9in x 3.3in) Precautions and Instructions for Use: 1. When the unit is unloaded, the measured output voltage is a phantom voltage; a load of at least 20W must be connected to measure accurate output voltage. 2. Input is AC power; output is also AC, not DC. 3. The stated 4000W refers to maximum capacity under resistive load conditions. Inductive load capacity is one-third of resistive load rating. Resistive loads include tungsten filament lamps, heating elements, etc. Inductive loads include series motors, etc. Use caution with electronic circuit board devices. 4. The metal casing of this product must be properly grounded.