This unique flywheel car connects students to the real-world use of kinetic energy recovery systems in modern cars. Operate the car with the drive wheels in the front or the rear. For free roll 2-wheel motion, flip the car over and push. The flywheel stores enough energy to help propel the car over small, low-profile obstacles and up ramps. No batteries required. Comes in our choice of assorted colors. Size, 2-4/10 x 3-6/10 x 2-1/2".