Review on Hikenture Skull Cap Helmet Liner: Thermal Winter Cycling Cap with Glasses Holes for Ultimate Comfort and Performance by Aaron Vang

Bought to wear under a bike or ski helmet so a little baggy when working properly. However, it detracts from comfort and feels a bit silly unless covered by something else (hence 4 stars). While under the helmet looks quite appropriate. UPDATED 2/2/2021 Never bought such a flexible skullcap. It turned out to be great for skiing. Used skiing for a week. Great for a little extra warmth and confusing under a good helmet in weather well below 0 degrees Fahrenheit. I wouldn't want to use it without a helmet because it's downright ugly and pliable. Conversely, I wouldn't want a tight-fitting skullcap under a helmet because it's a bit uncomfortable. At the moment I'm an application-specific skullcap person: tight for most applications; and a disk like this for use with a helmet.