The Tamiya 4-Speed High Power Gearbox H.E.  kit includes one brushed DC motor and all the gears and parts to build any of the four possible gear ratio configurations: 39.6:1, 47.6:1, 61.7:1, 74:1. The four gear ratio options give you the flexibility to choose the best speed and torque for your project.

Tamiya 72007 4-Speed High-Power Gearbox Kit

The kit includes step-by-step illustrated instructions in both Japanese and English. The kit can be built with just a screwdriver, but the instructions recommend having side cutters, pliers, and a modelling knife on hand.