Tamiya Mini Motor Low Speed Gearbox 4-Speed TAM70189 Mini Racer & Accys

GREEN FABWOOD 75 Type Plastic Crown Gear Single Double Reduction Gear Worm Gear (Original Version)

Tamiya America, Inc Double Gearbox L/R Independent 4-Speed, TAM70168

Tamiya 70103 Universal Gearbox Assembly Kit

1 X 72008, 4 Speed Worm Gearbox, HE by tamiya by Tamiya

Mini Motor Multi Ratio Gearbox 12-Speed

EUDAX 6 set Rectangular Mini Electric 1.5-3V 24000RPM DC Motor with 84 Pcs Plastic Gears,Electronic wire, 2 x AA Battery Holder ,Boat Rocker Switch,Shaft Propeller for DIY Science Projects

80Pcs Plastic DIY Robot Gear Kit Gearbox Motor Gear Set for DIY Car Robot

Tamiya America, Inc Mini Motor Gearbox 8-Speed, TAM70188

EUDAX 2mm Hole Plastic Belt Pulley Gears Combination Modulus Package Rubber Belts Band Plastic Model Accessories for DIY Robots Cars RC Toy Car Airplane

Engineering Design: A Project-Based Introduction