Hippity Hop,18" Giant Bouncy Balls Hopping Inflatable-Backyard Park Beach-Pparty (Yellow+Purple) Size: 18 inches,inner&outer meterials:inflatable nano material + nylon fabric. Right size for ages 3-6,cute design that kids love. Good for playing backyard,park and beach. Burns out energy allowing mom to relax. Inflates quickly (pump sold separately). Makes exercise fun! Try adult size and show the kids how it's done! Suggest fill 3/4 air into the hopper for 1st-time unfolding.