Celebrate every event, birthday party, graduation or celebration with beautiful 18" Foil Mylar Balloons. Helium Grade and designed for maximum floating time, choose from a wide range of colors! These Foil Balloons are Re-Inflatable, and feature a 1-way built-in Helium valve that locks in Helium for no costly wastage. Foil Balloons Float for Up to 2 Weeks!