SpringBots 3-In-1 Spring-Powered MachinesBuild three amazing self powered machinesa motorized robot, race car, and countdown timerall without batteries or electricity! The secret behind these fascinating models is the mainspring, a spiral shaped spring that stores energy when wound up and then releases it to power motion. Watch as the robot marches forward, the race car zooms up to 45 feet, and the countdown timer ticks down for up to six minutes using a clever system of gears, ratchets, and