3075-POLOLU 100:1 Micro Metal Gearmotor HPCB 6V with Extended Motor Shaft
This gearmotor is a miniature high-power, 6 V brushed DC motor with long-life carbon brushes and a 100.37:1 metal gearbox. 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 6 V: 320 RPM and 120 mA with no load, 30 oz-in (2.2 kg-cm) and 1.6 A at stall.