This is a great electric motor gearbox used for children's .The middle 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 20000RPMName:Electric Motor Gearbox length: Approx. 16.5cm / 6.5 inchHole Diameter: 1cm / 0.39 inchTorque: Motor GearboxMaterial:PP+PMcolour:blackPackage Contents:8 x DC MotorOnly 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. Note: 1. Please allow 1-3 mm error due to manual measurement and 1-3g weight error make sure you don't mind before ordering. 2. Due to the lighting of the photos and the difference of monitors, the pictures may not reflect the actual color of the real item. Please make sure you don't mind before ordering, thank you! About Shipping: 1.please pay attention to your delivery address such as: name, street, house number, doorbell/email without name, etc. is correct, or the order will not be delivered correctly. 2.All items will be shipped within 3 business days after the payment is received. Most times you will receive them within 8-12 days then. The specific delivery time is depend on circumstances. 3.During the shopping process, if you have any questions, please feel free to consult us, we will reply you within 24 hours, wish you a happy shopping!