On a long run in single-digit temperatures with a steady headwind, the Ciele HOTHCap is the insulated running cap that keeps the head warm with less bulk. A merino wool and recycled silk fill sits under a recycled polyester outer shell. Insulated ear flaps and neck protection fold up or down to match the conditions, and a durable water repellent finish adds protection against wet weather. What Our Gearhead(R) Experts Are Saying:"The vented panel on top let heat out on hard efforts, so my head stayed warm without getting soaked. Folding the neck protection up once I warmed up cooled me just enough, and I folded it back down for the windy stretches."