Our shell jackets have a technical membrane to help them withstand harsh weather conditions with heavy rain, wind and snow. The membrane is waterproof from the outside  but permits body heat and moisture to escape to keep you dry and comfortable. Waterproof jackets with a water column rating of 20.000mm or more can withstand heavy rain and wet snow for an extended time. A lower water column rating means the jacket can stand up to less heavy rain, but might have a higher breathability and therefore a higher comfort during high-intensity activities. Want to know more about our jackets and features? Look at our jacket guide.