Celebrate that special someone's birthday with this fun 18 inch round Birthday Holstein Cow Pattern foil mylar balloon! Combine a couple of these 18 inch 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