Features: 1203B DC Motor Speed Regulator controls the speed of a DC motor by adjusting Pulse-Width-Modulated (PWM). The input power range is DC 6V-28V . Duty Cycle adjustable range is 0%-100%. Operating instruction: Before you attempting to wire the controller, make sure power is off. WARNING: DO NOT REVERSE POSTIVE AND NEGATIVE POWER LOADS.THIS DAMAGE THE CONTROLLER. TO CHANGE MOTOR DIRECTION, INTERCHANGE THE POSITIVE AND NEGATIVE WIRES OF MOTOR. Color: picture color Material: PC + metal Size: 5 x 3.2 x 1.5cm Package Contents: 3 x DC Motor Speed Controller 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.