product description: Size: 3V – 250RPM Features: It is an excellent alternative to rusty or damaged DC gear motors on machines. The long shaft has a diameter of 3 mm and two terminals. Fine workmanship, durable, not easy to wear, light weight, high torque, low speed. Very suitable for DIY engines, robot models, small robots, electronic door locks, electronic DIY toy cars setc. specification: 1. Model: G12 – N20. 2. Material: metal. 3. Speed: 250RPM. 4. Rated voltage: DC 3V. 5. Shaft diameter: 3 mm. 6.Total length: 37 mm. 7. Motor size: 17 x 12 mm (length x thickness). 8.Cylinder size: 10 mm x 3 mm (length x thickness). 9. Mounting hole screws: M1.6*0.3mm(D*L). Packing list: 1 gear motors. [Worry-free Warranty]: Here, we offer a 90-day money-back risk-free purchase guarantee, which can be refunded or replaced in case of any dissatisfaction.