Of course, we don't recommend riding sans-helmet, but the Castelli women's Summer Cycling Cap might just be the ultimate do-anything summer cap. The flip-up bill is a bit shorter than the men's version, but the materials and design are almost the same. The microfiber front panel wicks moisture away from your skin, while the open mesh at the rear of the cap allows warm air and water vapor to escape. There's even a band of Velocity material around the base of the cap to pull moisture away before it can drip down your forehead into your eyes.