40 Inch Giant Jumbo Helium Foil Mylar Balloons (Premium Quality), Glossy Silver, Letter A Helium-inflation allow balloon to float. Floating time is about 12-168 hours (7 days) for indoor; 10-24 hours for outdoor. Easy to inflate using the a straw or an air handheld pump Long lasting. Reusable. Self-sealing valve for easy inflation and deflation. Shipped uninflated. Can be air filled or helium filled