4 speed gearbox review

This is what your basic DC motor gearbox looks like. The gear configuration helps to slow it down and provide more torque than just the motor spinning by itself.

I ordered this one from a robotic supplier named Pololu. The cost was around 12 bucks once shipping is factored in.

The instructions that came with the kit are a challenge to understand. Luckily they have great illustrations to guide you in the right direction.

You can arrange the gears in a way that gives you 4 choices of speed.
                                                                                                
Consider this an advanced project. Those gears are small and you really need to get it just right for a smooth operation. It took me about 2 hours of messing with it to finally get some decent results. If you do order this kit you might want to add on one of their DC transformers for only 5 bucks.