It helps to wick moisture, provides UPF30+ rating with excellent breathability, and the Smart Seam helps alleviate pressure points from your helmet. 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. You can also expect to stay cool and dry on the ride, thanks to the X-Static Performance Jersey mesh and power mesh side panels on the SPF Ultralight Skullcap.