The SealSkinz Trunch Waterproof Cycle Cap builds three layers into one thin profile: a polyester and nylon outer for durability, an Aquasealz membrane that blocks rain without trapping heat, and a moisture-wicking lining underneath. A raised peak keeps runoff out of the eyes on a wet descent, and a Coolmax sweatband handles perspiration on the climb back up. The close-fitting shape sits flat under a helmet instead of adding bulk. What Our Gearhead(R) Experts Are Saying:"My head stays dry through a full hour of steady rain, and I never once feel that clammy overheated moment I get from other waterproof caps. It disappears under my helmet so completely I forget it's even on until the sky opens up."