Features: 12V24V7A electronic stepless speed controller, direct current motor speed control switches, motor speed control switches Connect the red wire to the positive poles of the motor and the positive poles of the power supply, connect the black wire to the negative poles of the power supply, and connect the blue wire to the negative poles of the motor Direct current motors are easy to speed, have simple wiring, and are convenient to use, making them excellent substitute for damaged motors. Extra long knob screw to meet installation requirements Widely used in DC12V-24V electrical appliances. Adjust motor speed, control of car fan heater, defroster, fan speed regulation, etc This electronic continuously variable speed controller is upgraded fan heater controller with a radiator, ensuring better heat dissipation Specifications: Material: Aluminum Alloy Size: 63mm/2.48''x33mm/1.3''x33mm/1.3'', 53mm/2.09''x33mm/1.3''x33mm/1.3'' Type: With heat sink, Without heat sink Line Length: 11cm/4.33'' Power: 12V-24V 7A Package Includes: 1Piece Motor Speed Controller note: Please allow 1mm errors due to manual measurement. Due to the differences between different monitors, the picture may not reflect the actual color of the item.