These are Made of high quality aluminum foil, about 16 inch 0 to 100 Number Digit and 16 Inch Happy Anniversary Alphabets, 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 Metallic Balloons Features Every Alphabets From A to Z and Numbers, So You Can Mix And Match To Form Any Number Or Happy Anniversary Letters. Whether You'Re Celebrating A Big Anniversry, These Shining Happy Annivesary Gold foil Balloons Are Perfect For Your Celebration. Mix And Match With Coordinating Foil And Latex Balloons accessories16" Inches Happy Anniversary Balloon X 16 Alphabets16" Inches Number Balloon X 1Long Lasting Quality Can Be Use For Wall DecortionsAnniversary Occassions For Mom, Dad, Brother, Sister, Husband, Wife, Uncle, Aunty & Surprise Anniversary PartyThese are self-sealing balloons. Tying with fingers is not needed. It has Self-sealing and is reusable. The foil balloons automatically seal when you stop filling them ?Tying, twisting, or Putting a knot is not necessary.?hoto friendly. Numbers and Letter balloons simply can be used as props or to decorate your wall with them.