Made of a three layer Pertex Shield + material, they give you complete weather protection and dynamic breathability: the higher your output, the more water vapor the material is able to push out. The Firewall Pants are light and they thrive in mountain use but are naturally very capable in more laid back weather protection service as well. Three layer trousers are meant to be paired with long johns or tights, but when a summer rain shower catches up on you, it's ok to don them temporarily on top of a pair of shorts. Using them as your general trousers during a cool autumn hike or freezing point sports, you'll do best with either synthetic or thin Merino base layer pants. This updated model has a slightly thicker surface fabric compared to its predecessor: 40 vs. 30 deniers. The difference is not dramatic, but does increase the trouser's service life. - Waterpfoor, windproof and breathable - Three layer structure - 3/4 length waterproof YKK Aquaguard zippers on the sides offer excell