Tilley's LTM5 Airflo Hat in Khaki is one of the lightest hats on the market. It provides unparalleled sun protection and is designed to repel rain. It also has ventilation grommets with mesh for optimal breathability, as well as an anti-sweat band to wick away perspiration. Plus, the hat is backed by a lifetime guarantee - Tilley will replace it should it ever wear out.