These balloons is made of Aluminum Foil . High quality self-sealing balloon. When inflated with helium will float for several days. Requires helium. Great Party Favours / Outdoor Toys! These Lovely toy make the perfect party favours for baby shower, christening?birthday party. Great gift for kids!? ? The balloon will arrive uninflated. Most local card shops, party shops and florists are happy to inflate for a small charge.