Let your kids experience true outdoor fun as they wiggle, ride, and wriggle their way around the driveway, park, or patio. Wiggle cars are self-powered and require no batteries. Using gravity and centrifugal force, your children can race around like athletic race car drivers, the wind soaring through their hair. Now you can put your child's natural wiggling tendencies to work! The self-powered wiggle cars are built from high-density ABS plastic and designed to accommodate up to 150 lb. Best performance is achieved on smooth, flat surfaces, indoors, or outdoors.