Made of rainbow-colored plastic links, the Hoberman sphere expands and contracts. There's a hypnotic fascination in making the sphere expand and contract over and over again. How about trying the ballerina spin, the flip down or the hot potato? The sphere can also be a fashion accessory. Think spiked hat or, even better, space helmet. Another option is to hang the sphere as a mobile. Plenty of fun, the Hoberman sphere might get kids thinking about mechanical engineering and some folding/unfolding projects of their own. Original size expands from 9-1/2" to 30". Ages 4 and up.