Features: *The battery pack marked with 48V, 68V, 88V, 98V, 128VF or TV can be used, and its 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 connect the wire---fix the motor---install the case---tighten the screw---make sure that the square shaft of the head can be easily rotated without jamming---connect the power supply--- Press down the speed control switch so that there is no gap in the shell! Otherwise, there may be a buzzing alarm! *To prevent damage to the motherboard, please follow the requirements. *It has been tested before selling OK. Specification: *The product is suitable for 2106/161/169 brushless electric wrenches. *18V 21V Brushless Angle Grinder Drive Plate Polishing For Machine *General Control Panel Size:5.2*6.2CM *Brushless sensorless angle grinder drive control board general *Control board drive voltage: 18V (5 strings of lithium batteries, fully charged 21V), power 300W. Package Contents: 1*Control board 1*Switch Note: 1. The real color of the item may be slightly different from the pictures shown on website caused by many factors such as brightness of your monitor and light brightness. 2. Please allow slight manual measurement deviation for the data _x000D_