LOONBALLOON Bachelorette Balloons, 18in. Girls Night Out, Accent your bachelorette themed party with this 18in. round Bacherlorette Party Lace foil mylar balloon. The perfect balloon for your bachelorette party, this 18in. 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. Bacherlorette Party Lace Foil Mylar Balloon 18in.