Adopts double insulation; there will be no electric leakage if short circuit or SCR burn out. Can prevent peak voltage and electric surge; RC absorption and fuse to enhance the safety of use. Aluminum housing prevents easy damage; Tin filled prevents from heating when huge current. With protective cap and connection after; thicker and larger heat sink. Parameters: Operating voltage: 220V AC Maximum power: 4000W ( connected resistive load) Voltage regulation: Start of 10V, 10V-220V Dimensions: 85 X 58 X 35 MM Protection: Anti-spike, Surge, RC absorption (EOC) How to use: Adjustable power board; Connect this device with lamp or home appliance or electrical circuit, then turn the knob for dimming, speed, voltage, temperature control. Some Application: Electric oven, water heater, lamps, small motor, iron, etc. Package includes: 1x WINGONEER Voltage Regulator