The Sundried skull cap is fleece lined and snug, making it perfect for cold weather running and cycling in winter rain or snow. Super comfortable and insulating, your head will stay warm and allow you to keep training even in bad weather. Sundried's under helmet skull cap features reflective detailing around the entire perimeter meaning you will be seen in low light or when cycling or running at night. The Sundried cap is one size fits all with a snug and secure yet stretchy fit, meaning it will contour to your head and provide the ultimate comfort. The luxury material in Sundried's cycling skull hat is breathable, sweat wicking,and thermal. Sundried is a British premium ethical activewear brand and your satisfaction is our highest priority. If there are any questions or concerns about your product, please let us know and our dedicated customer services team will be happy to help.