LOONBALLOON Retirement Balloons, 17 inch HAPPY RETIREMENT. Accent your retirement themed party with this 17in. round Happy Retirement Celebration foil mylar balloon. The perfect balloon for your retirement party, this 17in. party balloon is great for setting the scene! This balloon includes a self-sealing valve, preventing the gas from escaping after it’s inflated. The balloon can be inflated with helium to float or with a balloon air inflator. Balloon arrives uninflated.