1510YSY is the part number for a 6-amp Curtis Electronic Motor Speed Controller. The controller is used to control the speed and direction of a DC motor with various voltage options up to 85 V. It comes with a 4-pin terminal block, a pulse width modulation (PWM) control line, and adjustable potentiometers for zero-speed, maximum-speed, acceleration, and deceleration. The device is also equipped with over-current and short-circuit protection and a thermal protection circuit for the motor.