Brushless Electric Wrench Drive Board Controller Board Power Tool for Electric Wrench Brushless Angle GrinderThe product is suitable for brushless electric wrenches.18V 21V Brushless Angle Grinder Drive Plate Polishing Machine. Brushless sensorless angle grinder drive control board general Control board drive voltage: 18V (5 strings of lithium batteries, fully 21V), power 300W. Before testing the machine, you must first connect the wire---fix the motor---install the case---tighten the screw---make sure that the square shaft of the can be easily rotated without jamming---connect the power supply--- Press down the speed control switch so that there is no in the shell! Otherwise, there may be a buzzing alarm! To prevent damage to the motherboard, please follow the requirements. Suitable for: brushless electric wrenches Colour:black Material:plastic Package Contents: 1 * Power Tool Controller Board Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.