LOONBALLOON Dinosaurs Balloons, 18 inch HAPPY BIRTHDAY DINOSAURS 2 pcs, Accent your dinosaur themed party with this 18in. round Birthday Colorful Dinosaurs foil mylar balloon. The perfect balloon for your dinosaur party, this 18in. party balloon is great for setting the scene! This balloon includes a self-sealing valve, preventing the gas from escaping after it’s inflated. The balloon can be inflated with helium to float or with a balloon air inflator. Balloon arrives uninflated.