4X 7V-12V DC Brushless Driver Board Controller for Hard Drive Motor 3/4 Wire Speed Control Board The driver board can drive hard disk brushless motors ,CD-ROM brushless motor and so on ,the Micro-3-wire or 4-wire without hall brushless motor, It's have reverse voltage protection , Over current protection , Phase inversion control Driver voltage: DC7-12v Working voltage: less than equal 1.2A Speed adjust: 0%-100% Material: PCB Color: green Note: Brushless motor line of receiving terminal drive plate must be pressed sturdiness, poor contact will lack of phase operation and burn out the chip.Board terminals fixed screw clearance, please use coarser line connected to the board. How to identify four line motor public port: use the resistance of the multimeter x gears test this four terminal,One of the terminals and the other three terminal resistance value of the minimum and equal So it's COM terminal Size: 6x4.5cm/2.36x1.77 inch Quantity: 4Pc Package Contents: 4 x 7V-12V DC Brushless Driver 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.