Tamiya 72008 4-Speed Worm Gearbox Kit

The primary feature of this gearbox is a worm gear, which locks the output shaft when the motor is not turning. Its high gear ratios of 84:1, 216:1, 555.4:1, and 1428.2:1 make this gearbox appropriate for small walking robots, lifting mechanisms, and other applications where high torque is desired.