From the Manufacturer
The Shake 'N Go Racers Superman Racer is a licensed car based on the character Superman. The basic play pattern consists of shaking the car, which activates a motion switch. This motion switch relays the amount of shaking to the internal IC, which in turn plays sound effects that sound like an engine "revving up". As the child shakes the car more, the engine "revs" higher and higher until it is fully charged up. When the child places the car on the ground, there is switch in the front axle that when triggered, engages the motor and the car takes off with the IC playing the appropriate sound effects. There is a direct correlation between the amount of shaking and the speed of the motor and the length it runs.
Product Description
Look! Up in the sky! It's a bird! It's a plane! It's Superman! Just shake it up to start the engine. The more you shake it up, the longer it goes. Hear cool Superman phrases every time you let it go. It's super-fun! Requires three "AA" batteries, not included. Measures 2.5"L x 3.5"W x 6"H.