AER Splash™ water repellent technology keeps your hat from getting water logged. The water beads up and runs right off the hat, almost like magic!HyperPoly+™ fabric for heightened sweat stain prevention (no white sweat lines)Hidden AER Run Pocket! Store a key or fuel right inside your hat (select styles)Ultra lightweight; light as a feather fabricExtreme sweat wicking material to take on your toughest runs/adventuresMaximum durability for longer lasting colors (stays fresh as the day you got it!)Low maintenance care. Wear, sweat, hand rinse cold (only), REPEAT! No washing machine required to stay fresh!