Dorky? You bet. Maybe you’ve seen this advertised in the back pages of your favorite running, cycling or fitness magazine. It’s a kooky ad and easy to dismiss, but the performance benefits of this simple elastic device are undeniable. Say goodbye to rivulets of stinging sweat flowing into your eyes on long, hot climbs. The Halo II headband really is a godsend—its simple design uses a silicone gutter to divert sweat from running down the front of your face, and its thin, cushioned material guards against the chaffing effect of long-deteriorated foam helmet padding. The headband comes in nine different color options—all of which are invisible under your helmet, anyway—and is about the best $13 gear investment going.