? PACKAGE INCLUDES-- Totally 13 Pcs "Happy Birthday" letter balloons. Each letter balloon measurement about 16 Inch. ? MATERIAL-- Made of high quality aluminum foil balloons,environmental protection materials. It is safe and non-toxic, self sealing helps the balloons maintains for nearly 1 week without leaking or losing air. WIDELY APPLICATION-- Use for birthday, birthday party, wedding, baby shower,outdoor party, home party, celebrations and other on-site decoration. ? SUITABLE FOR THE CROWD-- Perfect for decorating the babies, kids, adults birthday party with this lovely 'HAPPY BIRTHDAY' Foil letter balloon banner. Best Happy Birthday Decoration Kit set for your family. The letter foil baloons can be filled with helium or air but it cannot float. ANY 16" alphabet ballons cannot float with helium. Metallic ballon can be filled with helium and float. They are 10" in size.