Obstacle House! Spider Scramble US PATENT # 9,047,786. "A Parents' Choice Recommended Award Winner 2013!" Children practice coordination and agility while gaining upper and lower body strength by engaging in a moving lateral plank. Stickers located in the bottom corner of each mat guide very young children as they put together the exercise puzzle. Patent pending. Made of lightweight, washable, durable interlocking 3/4 inch thick EVA foam mats. One of twelve kid-healthy sets in the Obstacle House! series.Free BIG BLUE BAG included for easy storage of your sets!