This is a great electric motor gearbox used for children's cars. The middle gear is made of metal which is more sturdy and durable. It will make quite low noise and more wear-resistant. It will be a great replacement part for your broken or old ones. The voltage is 12V and the speed is 20000RPM Name:Electric Motor Gearbox total length: Approx. 16.5cm / 6.5 inch Hole Diameter: 1cm / 0.39 inch torque: Motor Gearbox Material:PP+PM colour:black Package Contents: 2 x DC Motor Only the above package content, other products are not included. Note: Light 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.