These are Made of high quality aluminum foil, about 16 inch in size, thick and auto-sealing, no leaks, can last for days when inflated. Give Your Big Party A Personalized Presentation With Foil Balloons! This Collection Of Balloons Features Cursive Happy Birthday Alphabets Letters Foil Balloons , So You Can Mix And Match To Form Any Number Or Name. Whether You'Re Celebrating A Big Birthday, These Shining Cursive Happy Birthday Gold, Silver,Rose Gold foil Balloons Are Perfect For Your Celebration. Mix And Match With Coordinating Foil And Latex Balloons, Polka dot balloons & balloon accessoriesCursive Stylish Silver Happy Birthday Balloon BannerIncludes Essential Accessories ?Straws to fill them up and a ribbon to hang themReusable And Easy To InflateColour: SILVERAvailable Cursive Happy Birthday Alphabet Letters