Accent your space or astronaut themed party with this 18in round Birthday Astronaut foil mylar balloon. The Perfect balloon for your space or astronaut party, this 18in Qualatex 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.