Feature: 1. Wide Application: The speed controller can regulate speed, temperature, voltage, and light. It is widely used in exhaust fans, filament bulbs, electric furnaces, angle grinders, marble machines, and blowers. Note: It cannot be used with electrical appliances containing circuit boards or capacitive electronic components, such as microwave ovens, induction cookers, rice cookers, water pumps, washing machines, LED or energy-saving lights. 2. High-Quality Material: The variable speed controller features a high-quality ABS plastic insulated flame-retardant housing that resists discoloration, deformation, cracking, and high temperatures. Internal components are made of thickened phosphor bronze for reliable performance and extended service life. 3. High-Precision Display: The fan speed control switch includes a precision voltage-regulating knob with high accuracy and stable performance. Control accuracy reaches 1 volt. The digital display screen clearly shows the working voltage of the device, and the LED light enhances visibility of real-time voltage readings. 4. Overload and Overvoltage Protection: The variable speed fan controller includes an independent switch with overload and short circuit protection. When the instantaneous current exceeds 15 amperes, the switch automatically powers off to protect the controller. The indicator light allows users to monitor the switch status. 5. Back Hook Design: Designed for convenience, the controller features a hook on the back, allowing it to be hung on a tool bag or kit. This makes it easy to carry and use. The plug-and-play design ensures simple and practical operation. Specification: Item Type: Electronic Voltage Governor Material: ABS Color: Black Package List: 1 x Electronic Voltage Governor