Critter cruiser is an exciting pet powered exercise car for hamsters and gerbils. Critter cruiser's adjustable racing wheel allows for the car to work in three different ways. First, when the comfort wheel is in the top position, exercising critters spin the wheel and the critter cruiser remains stationary. Interactive fun begins by adjusting the comfort wheel into the middle position. In the middle position, you can watch your pet turn the wheel and roll their critter cruiser on any flat surface. Measures 6 x 12 x 9 inches.