2 speed...how to do it?

The only website I've found that says anything about a multi-speed bit is in chinese and cannot be displayed or translated by my browsers, but it appears the site sells them and doesn't tell you how to make your car multi speed.

I know some of you on this board have 2 speed cars...want to help me out here? How do you do it? Thanks!

[MicRoMaN]

II thought 2 speed was just going in reverse and forwards? Am i right? If i am isnt it already able to do that?