Speed Control Knob: This knob can adjust motor speed and display in real time. There are 5 controllers in different power and you can you need. It has compact size, high precision, wide speed controlling range, and long service life. Built-in capacitor, supporting /CCW rotation. Widely used in packaging, printing, food, electronics, instruments, clothing industry production for speed drive device. Connect and , the motor rotates in direction; connect and CCW, the motor rotates in reverse direction. Specification: Model: UX-52 Input Voltage: AC 220V 50Hz Optional Power: 15W, 60W, 120W, 250W, 400W Output Speed: 0-1450rpm Speed Adjustable Range: 0-1450rpm Operation Mode: Manual Precision Speed Change Rate: less than or to 2% Steady Speed Precision: 10 Port: Pin Size: . 10 x 10cm/3.9 x 3.9inch Weight: . 322g / 11.4oz Colour: Black Material: ABS Package Contents: 1 x Motor Speed Controller Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.