Wheel them back to get new skills speeding ahead! The "rev up" mechanism inside each of these four cars and trucks makes it easy for babies and toddlers to get big acceleration with just a little input: Pull back one of the soft vehicles--then release to see it zoom off across the floor! Wheel them back to get new skills speeding ahead! The "rev up" mechanism inside each of these four cars and trucks makes it easy for babies and toddlers to get big acceleration with just a little input: Pull back one of the soft vehicles--then release to see it zoom off across the floor!