Features: The item is a professional and practical 4000W high power SCR electronic voltage regulator controller The Voltage Controller is mainly made of durable PCB board and electronic components, and convenient to connect wire It is suitable for dimming, speed and temperature control. Gently rotate knob cap, can adjust flexibly, do not need to add any element, the product is practical, convenient. The product is mainly used for resistance load, such as electric furnace filament incandescent light bulb, etc. Specifications: Product name: 4000W AC voltage regulator SCR model: BTA41-800B Maximum power: 4000W (suggest load within 2000W) Efficiency: < 90% Operating voltage: 220V AC Regulating voltage: AC 0-220v Size: 10 x 6.8 x 4cm / 3.94 x 2.68 x 1.57in Knob inner hole: 6mm Weight: 144g Package included: 1 x Voltage Speed Controller Note: 1. Load must be connected before voltage is measured 2. The product is mainly used for resistance load, such as electric furnace filament incandescent light bulb, etc.