Pros: Thin to fit under helmet. Still warm.

Cons: Seams can rub in and aggravate your head.

Recommendation: Great under helmet skull cap to keep in the heat and keep the wind out.

Pros: thin, lightweight, very warm, price

Recommendation: fits under my helmet so well I cant tell its on. keeps my head very warm on the coldest days so far(30 degrees). great coverags of my entire head and ears.