A cycling cap either works under a helmet or it doesn't — there's no middle ground when you're two hours into a summer ride and sweat is pooling at your brow. The Castelli A/C 2 Cycling Cap addresses the ventilation problem directly with mesh side panels that allow airflow where traditional cotton caps trap heat, while the short brim still handles its primary job of keeping sun and sweat out of your eyes. This is Castelli's warm-weather answer to the classic cap design, built for riders who refuse to abandon the form factor even when temperatures climb.

The mesh construction runs along both side panels, creating a channel for moving air that works with your helmet's own ventilation system rather than blocking it. When you're climbing at low speeds and helmet vents become less effective, the cap's breathability helps compensate. The polyester-blend fabric wicks moisture away from your forehead, and the short brim flips up cleanly when you need unobstructed vision through corners or when the sun angle changes.

Fit follows the classic cycling cap profile — snug enough to stay put under a helmet without creating pressure points, with enough structure to maintain the brim's shape through repeated wear and washing. The elastic rear band provides adjustment without bulk, sitting flat against your head where it meets helmet padding.... Read More