30 inch Foil Mylar Balloons for Wall Decoration (Premium Quality, Air or Pure Helium Fill Only), Glossy Silver, Number 30 Pure Helium (90% or higher) inflation allow balloon to float. Shipped uninflated. Can be air filled or pure helium filled. Easy to inflate using the a straw or an air handheld pump. Easily hung on strings from ceilings or attached to wall with tape Reusable. Self-sealing valve for easy inflation and deflation. DON'T inflate with diluted helium (90% or lower)