Features a tiny straw for quick air-filled inflation. These balloons are designed to be inflated with air only and do not float with helium. Celebrate that special someone's birthday and get the party started with this fun 41cm shaped letters Happy Birthday Kit - Multicolour foil mylar balloon! Combine a couple of these 41cm Northstar balloon designs with a few of our birthday latex balloons to create a bouquet cluster to give someone as a special gift or to use as birthday party decor. 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.