Features: This is a easy-to use voltage regulator for controlling light brightness or speed. Designed with large heat sink for better heat dissipation. Convenient to use, simply connect input terminals to either live wire or neutral wire(220V) and output to load, then rotate knob to control voltage. There is a digit display showing output voltage, which is clear to read. Could be widely used as controller for ceiling fan, engraving grinder, conveyor belt, angle grinder, etc. Specifications: Input Voltage: AC 220V Size: 12.5*6cm/4.9*2.4in Weight: 198g(approx.) Note: Please connect to load first, then adjust voltage. Package Includes: 1 x Voltage Regulator 1、This is a easy-to use voltage regulator for controlling light brightness or speed. 2、Designed with large heat sink for better heat dissipation. 3、Convenient to use, simply connect input terminals to either live wire or neutral wire(220V) and output to load, then rotate knob to control voltage. 4、There is a digit display showing output voltage, which is clear to read. 5、Could be widely used as controller for ceiling fan, engraving grinder, conveyor belt, angle grinder, etc.