The cap fits under my helmet and kept my head dry, and warmer than with out. Cold rain off the head is good. In a harder rain water went under my rain jacket when on my bike. For better dryness I need a rain hood. I like the cap. My head circumference is 42.5 inches. The max stretch limit and max recommend head size. The cap is a bit tight. Two cap sized with overlapping sizes are needed I think.
