Features:* The product is suitable for Dayi 2106/161/169 brushless electric wrenches. Has been tested before sale OK.* 18V 21V Brushless Angle Grinder Dayi Disc Grinder* Overall Control Panel Size 5.3*6.3CM* Brushless Sensorless Angle Grinder Drive Control Board General* Control Board Drive Voltage: 18V (5 Strings of Lithium Batteries, Fully Charged 21V ), power 300W.* You can use the battery marked 48V, 68V, 88V, 98V, 128VF or TV, and its voltage is actually 18V (5 series of 2 parallel 10 cells or 5 series of 3 parallel 15 lithium batteries, fully charged 21V) .* Before testing the machine, you first need to connect the wire --- fix the motor --- install the housing --- tighten the screw --- make sure the square head shaft can be rotated easily without jamming --- connect the power supply --- press the switch speed control so that there is no gap in the coating! Otherwise, a buzzing alarm may occur!* To prevent damage to the motherboard, please follow the requirements. Package includes: 1 * control board 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.