Pololu - Tamiya 70190 Mini Motor Multi-Ratio Gearbox (12-Speed) Kit

Tamiya’s 12-speed multi-ratio mini motor gearbox features a more compact 030-form-factor brushed DC motor driving a single gear train that can be assembled to have one of twelve gear ratios: 4.6:1, 5.1:1, 9.7:1, 10.8:1, 20.4:1, 22.6:1, 42.8:1, 47.5:1, 89.9:1, 99.8:1, 188.7:1, or 209.7:1.

Pololu - Tamiya Motors and Gearboxes

Pololu 1682 - Tamiya 70188 Mini Motor Gearbox (8-Speed) Kit - Kamami on-line store

Tamiya 12 speed motor gearbox assembly

MINI MOTOR MULTI-RATIO GEARBOX (12-SPEED)

The Tamiya 75026 Mini Motor Set is a more powerful brushed DC motor for the Tamiya Mini Motor Gearboxes.

Tamiya 75026 Mini Motor Set

Pololu - Tamiya 70190 Mini Motor Multi-Ratio Gearbox (12-Speed) Kit

Tamiya Universal Gearbox Kit in Canada Robotix

Tamiya 70190 Mini Motor Multi Ratio Gearbox - Toko Komponen Elektronika & Robotik

Pololu - Tamiya 70189 Mini Motor Low-Speed Gearbox (4-Speed) Kit

Tamiya 70189 Mini Motor Low-Speed Gearbox (4-Speed) Kit

Tamiya 70188 Mini Motor Gearbox (8-Speed) Kit

Pololu - Tamiya 70190 Mini Motor Multi-Ratio Gearbox (12-Speed) Kit

Tamiya Twin-Motor Gear Box - RobotShop