Well, "booster" chassis (chassis capable of boost), are two speed. On their controllers, there is a button on the top right for shifting your car into "second gear." When not pressed, the car goes slower than a regular Microsizer. But when the button is pressed, it "boosts" up to the speed of a regular Microsizer. What's the point? "Shifting down" is great for bit tracks (tracks made for these cars) with lots of turns. Then, when you reach a straightaway, punch the button.
