The Up In & Over Dinosaur Bop Bags are inflatable punching bags for high energy, Jurassic-loving kids. The three assorted options are inspired by the T-Rex, Raptor and funky-headed Parasaur. These bags are built for punching, kicking and tackling - yet theyï؟½re incredibly safe and possibly therapeutic for rambunctious boys and girls. Just fill the built-in water chamber for a stable base thatï؟½s much less of a hassle than sand. The safety valves provide air retention during the bop bag action while speeding up inflation and deflation.