SMO 4 Axis TB6560 CNC Stepper Motor Driver Controller Board Toshiba TB6560AHQ chip - High power, maximum 3.5A drive current . Overload, over-current and over-temperature safety - Full protection for your computer and peripheral equipment . Relay spindle interface - Outputs Max. 36V 7.5A for spindle motors or coolant pump (only one device can be powered by this output!) Full closed-type optical isolation to protect the user's computer and equipment Four control inputs (divided into pairs of knives) - Allows setting of limit and emergency stop.