Quantity: 1 Accent your hot air balloon birthday themed party with this 18 round Birthday Hot Air Balloons foil mylar balloon. The perfect balloon for your hot air balloon birthday party this 18 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.