1000:1 Micro Metal Gearmotor LP 6V with Extended Motor ShaftPololu
This gearmotor is a miniature low-power, 6 V brushed DC motor with a 986.41:1 metal gearbox, making it a great choice for applications requiring fine control at very low speeds. It has a cross section of 10 × 12 mm, and the D-shaped gearbox output shaft is 9 mm long and 3 mm in diameter. This version also has a 4.5 × 1 mm extended motor shaft.
Key specs at 6V: 14 RPM and 40 mA with no load, 70 oz-in (5 kg-cm) and 0.36 A at stall. (Note: stall torque and current specifications are theoretical values; stalling the motor will damage the gearbox.)