I've had this hat for 6 months and I wear it on every ride under my helmet. It's extremely lightweight, it wicks away all sweat, and it protects my bald head from the sun. The fit is perfect. It's not too loose and not too tight. My head/hat/helmet measurements are 58  cm. I also have the Headsweats Spin Cycle hat which is nice but I don't often wear it because it's just not as comfortable as the Shorty Beanie and I've gotten used to not having a visor on my helmet. I also tried the Halo skullcap and it's a nice product but the fabric is too heavy for use here during the summer in SW Florida where it's extremely hot and humid. The Halo would be nice for winter though. The Headsweats Beanie does provide some warmth during cold weather but it's so light you can still feel the cold air whipping through. I like this hat so much that I've since bought another Headsweats classic as a backup. To me it's essential piece of cycling equipment.