We’re not asking how or why, but the folks at Hydro Flask have turned their water bottle expertise into making the season’s best hat. It’s airy light and superbreathable but structured with a rigid brim. It also doesn’t lose its shape, so we stuffed it in the tiniest crevices of our packs without ruining it. Better yet? The Crushable Hat is waterproof. In addition to keeping the sun off our faces, it protected us from driving rain on Mt. Washington in New Hampshire.