Trail running in freezing temperature or piste bashing for the day? The Hydropore Cap from Jack Wolfskin will keep your head warm. The sides are specially shaped to protect your ears. And it's so thin and light it's ideal to wear under a ski helmet. The stretchy fabric wicks perspiration effectively and dries fast. It also benefits from a special anti-odour treatment. And there's another advantage when you're up in the mountains: the fabric protects your head from UV rays.