Beth Gillette for Cosmopolitan Although I’m almost 30, I’ve only been to two bachelorette parties. But at both of them, I received the same gift: Grace & Stella Eye Patches . And according to all of my friends and other Cosmo editors who have been on bachelorette trips, they’ve also received these same ones. Under-eye patches at the bach party totally makes sense. After a night out celebrating the bride, the first thing I’m doing is pouring a cup of coffee, sticking on an eye patch, and sitting in silence. And this pack from Grace & Stella is under $30 for 24 pairs, making it uber affordable to stock in a bunch of welcome goodie bags. It’s really the perfect gift. But do these patches actually work? What makes them different from all the $$$ ones on the market? I investigated. About the patches: These gold, gel eye patches are packed with hyaluronic acid and glycerin to help moisturize your skin, which is honestly the first step of defense against tired-looking eyes.…