Features: Adopts double insulation; there will be no electric leakage if short-circuit or SCR burn out. Can prevent for peak voltage and electrical surge; RC absorption and fuse enhance usage safety. Aluminum for case prevents it from easy damage; filled tin prevents it from heating when in huge current. With protective cap and connection post; thicker and larger heat sink. Wide application: electric furnace, water heater, lamps, small motor, electric iron etc. How to use: Adjustable Power Supply Board; connect this device with lamp or home appliance or electric circuit, then rotate the knob for dimming, speed, voltage, temperature control. Some Applications: Electric furnace, water heater, lamps, small motor, electric iron etc. Specifications: Working Voltage: AC 220V Maximum Power: 4000W (connected resistive load) Voltage Regulation: Begin from 10V, 10V-220V Protection: Anti-spike, Surge, RC absorption (EOC) Size: 85x65x38mm/3.35x2.56x1.5" Quantity: 1 Pc Note: Please allow 1-3mm error due to manual measurement. pls make sure you do not mind before you bid Due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! No Retail Package Package Contents: 1 x Voltage Regulator