Shop name: Chong Qing Shuo Yue Ke Ji You Xian Gong Si The product is compatible with Dayi 2106/161/169 brushless electric wrenches. It has been tested before sale. 18V 21V Brushless Angle Grinder Drive Plate Polishing Machine Dayi Universal Control Panel Size 5.2x6.2CM Brushless sensorless angle grinder drive control board universal Control board drive voltage: 18V (5 strings of lithium batteries, fully charged 21V), 300W The battery pack marked with 48V, 68V, 88V, 98V, 128V or TV can be used, and voltage is actually 18V (5 series 2 parallel 10 cells or 5 series 3 parallel 15 lithium batteries, fully charged 21V) Before testing the machine, you must first connect the wire—fix the motor—install the case—tighten the screw—ensure the shaft of the head can be easily rotated without jamming—connect the power supply—press the speed control switch so there is no gap in the shell! Otherwise, there may be a buzzing alarm To prevent damage to the motherboard, please follow the requirements Color: As shown Material: Plastic + Metal Type: A Package Contents: 1 x Control board 1 x Switch Only the above package content, other products are not included Note: Light and different displays may cause the color of the item to vary slightly from the real thing. The measurement allowed error is +/- 1-3cm