Outdoor Research Novo Watch Cap

under helmet cap
This hat worked great under my ski helmet. It is very thin so helmet still fits correctly. It helped with that small space on my forehead between helmet and googles, that is sometimes exposed and gets cold. It does flatten my hair out so don't expect to have good looking hair when you take it off. Runs a tad small.

Nice beanie for active wear
The nylon/polypro bilayer material has a good balance of light wind protection, breathability and wicking. This beanie is great for x country skiing, running, biking, etc. For 20F cold I wear a thicker regular hat + hood on top until I get up to sweating temperatures. Normally I wear as little body layers as possible, since stuffing a hat in your pocket is much easier than a shirt. This hat is much thinner than a regular hat, but a bit more than a power dry or cap 4 type polyester beanie. I live in the balaclava with the same material when alpine skiing. At 0F I switch to the balaclava for x country as well. The hat also works over the ears or above them, although the look is "functional" in either case.

All-weather
Great fit, great material, all-weather beanie. Have ordered 4 in the past 2 years. Hope they keep making it. Priced right where it should be.