The product is suitable for 2106/161/169 brushless electric wrenches. 18V 21V Brushless Grinder Drive Plate Polishing Machine General Control Panel Size 5.2x6.2CM Brushless sensorless grinder drive control board general Control board drive voltage: 18V (5 strings of lithium batteries, fully 21V), power 300W The battery pack marked with 48V, 68V, 88V, 98V, 128V or similar can be used; actual voltage is 18V (5 series 2 parallel 10 cells or 5 series 3 parallel 15 lithium batteries, fully 21V) When testing the machine, first connect the wire, fix the motor, install the case, tighten the screw, ensure the square shaft of the head rotates freely without jamming, connect the power supply, and press down the speed control switch so that there is no gap in the shell; otherwise, a buzzing alarm may occur To prevent damage to the motherboard, follow all instructions carefully Color: As shown Material: Plastic + Metal Type: B Package Contents: 1 x Control Board Only the above package content is included; other items are not included Note: Light and different displays may cause the color of the item to appear slightly different from the real thing. Measurement allowed error is +/- 1-3cm