Hard disk brushless motors, CD-ROM brushless motors, and micro 3-wire or 4-wire without hall brushless motors can all be driven by the driver board. It is protected against reverse voltage. Protection against overcurrent and phase inversion Voltage of the driver: DC5-12v 1.2A is the working voltage. Adjustable speed: 0%–100% Note: The receiving terminal drive plate's brushless motor line needs to be pressed firmly; a weak contact will cause the chip to burn out and lose phase. Please use a coarser line attached to the board as the screw clearance on the board terminals is fixed. How to locate the public port for a four-line motor: Test these four terminals using the multimeter's resistance * gears. One terminal's resistance value should be at least equal to the other three terminals'. It is a COM terminal, then. The kit measures 63*46 mm (2.36"*1.77").