A new type of bi-directional high- thyristor is used, because the current can 25 A, which solves the problem of over-current caused by too small resistance of the electric furnace wire in the case of cooling. The product can easily adjust the output voltage, between 50 and 220 volts, for the of electrical equipment with different voltage requirements. Thyristor is mainly used for resistive load (electric filament incandescent lamp, etc.). single-phase AC motors are also available (but not guaranteed). The product is suitable for controlling different electrical equipment, such as electric lamps, fans, motors, etc. The ultimate resistance load of the product is 2000 W. It should be reduced for a long time. It is suggested the resistance load should be less than 1000W at room temperature (key parameters, please note). Specification: Voltage: 220V : 2000W (Resistive load ultimate ) Voltage adjustment: 50-220V AC Board: High Temperature Resistant FR-4 Circuit Board Colour:As shown Material:Composite material Size:48MMx60MMx28MM Package Contents: 2 x Controller Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.