Features: Wide Voltages: Wide voltages input 7-70V, output current 30 A(Please refer to the recommended power ranges for actual use current. It is recommended that 12V within 250W, 24V within 350W, 48V within 450W, and 60V within 500W. ) Speed Controller Knob: The knob has a switches function, which can control the motor speed. Adjustable potentiometer flexible cable can be separateds, the cable length is 15CM. 30 A Fuses: This set contains 30 A fuses to prevent shorting of the motor interfaces. Double protections of your Motor and Motor Speed Controller. Note 2: If there is a forward-reverse circuit regulator on the childrens car, please be to connect the speed controller between the power supply and the forward -reverse circuit regulator of the childrens car. Otherwise, the speed controller may be damaged. Precautions: The module is a motor speed controller and cannot be connect to power. The power of the input power supply must be 1.5times the rateds power of the motor to make the motor work (note: the input voltages and the rateds voltages of the motor must be consistent). Specifications: Material:Stainless Steel Size:Approx.9x5.9x3.4cm/3.54x2.32x1.34" Package Includes: 1 Set Speed Controller note: Please allow 1-2cm errors due to manual measurement,Please make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.