Thomas the Tank Engine I Sing Tap-To-Play round-shape (28 inch) mylar balloon. Make Thomas sing "Happy Birthday" to you. Plays "I think this calls for a celebration..." song. This Thomas super shape foil balloon is a great addition to your child's Thomas train theme birthday party! Ready to Inflate with Helium air. The balloon is sold un-inflated. Balloon measures 28 inch (71cm) in diameter. Uses Xtra Life technology. Recommended for ages 3 and up.