Ditching the brim doesn't mean ditching the cap. Giro's SPF30 Ultralight Skull Cap keeps the under-helmet layer that road and gravel riders reach for on hot days, minus the visor, so all you're left with is a thin, barely-there liner. It helps to wick moisture, provides UPF30+ rating with excellent breathability, and the Smart Seam helps alleviate pressure points from your helmet. If you shave your head, run a thinning hairline, or just don't love sunscreen dripping into your eyes at every rest stop, this is the fix.

The fabric is where this one earns its keep. This ultralight, ultra-thin skullcap provides SPF 30 sun protection for big rides, built from 96% polyester and 4% X-STATIC fiber with an X-Static Performance Jersey mesh top panel and power mesh side panels for breathability. The mesh construction lets airflow move through your helmet vents instead of trapping heat against your scalp, and it pulls sweat off your head before it soaks into your helmet padding. That last part is a quiet win over a full season, since it keeps your pads drier and cleaner.

Designed to be worn under a helmet, it is thin enough to fit without bunching and light enough to practically disappear when you put it on. An elastic rear panel offers a wide range of fit, and smart seams help alleviate pressure points when worn under a helmet. Real-world note on sizing: this runs on the snug side of one-size-fits-most, so if you've got a larger-than-average head, expect a close fit rather than a loose one. For most riders that snugness is exactly what you want under a helmet, since a loose cap shifts around and bunches when you sweat.