Pololu 100:1 Metal Gearmotor 20Dx44L mm 12V CB

These small brushed DC gearmotors can deliver a lot of power for their size. This version has a 12V brushed DC motor with long-life carbon brushes combined with a 100:1 metal spur gearbox. The gearmotor is cylindrical with a diameter of 20 mm, and the D-shaped output shaft is 4 mm in diameter and extends 18 mm from the face plate of the gearbox. Key specs at 12 V: 140 RPM and 90 mA with no-load, 85 oz-in (6.1 kg-cm) and 1.6 A at stall. Note: the gearbox torque limit is 70 oz-in (5 kg-cm); see detailed description for important product limitations.