Feature Powerful FunctionPowerful ac motor speed controller with variable thyristor and electronic voltage regulator. With universal socket and power supply light, and heat dissipation connector for quick heat dissipation. High QualityAdopting metal shell structure, high temperature resistance, flame retardant, not easy to rust. Core chip adopts high power thyristor. Which with adjustable button for stepless voltage regulation. Safety DesignNo delay, surge protection, anti-spike, rc absorption multiple protection. Input alternating current, the output is also alternating current, not direct current. This voltage controller product is a metal housing and must be securely earthed. Applicable Electrical AppliancesVariable voltage regulator is suitable for electric stoves, water heaters, tungsten filament lamps, small motors, electric soldering irons, fan speed control, etc. Many MOTORS do NOT support voltage regulation (for example, single-phase motors, dual-value capacitor motors, asynchronous motors, pumps, etc. are NOT supported.) NOTE: The input voltage is 0-110V, then the output voltage is 0-110V. The input voltage is 0-220V, then the output voltage is 0-220V. So both 110v and 220v can be used as the input voltage, But both cannot work at the same time. NOTE: The above mentioned 4000 W refer to the maximum power when working under ohmic load. The inductive load is 1/3 of the ohmic load. So it can only be used with devices within 100-2000W. Specification Model: NHT-4000W Material: aluminum Color: black Input voltage: AC110 V Output voltage: 0-220 V Voltage adjusting range: 0-220 V Rated current: 9A Max current: 18A Package list: 1 * SCR Voltage Regulator