Combining the warmth and comfort of our favorite lightweight puffy jacket and the reliable waterproofing of a rain jacket, the Mammut Alto Light 3-in-1 HS Hooded Jacket is designed to adapt to any weather. The 3-in-1 design features a waterproof shell with a zip-in, insulated liner jacket to keep us comfortable whether it's cold, wet, or some mixture of both. The removable inner jacket is made with zoned Loopinsulation which traps heat close to our body, and the shells Mammut DRY membrane keeps pouring rain and heavy snow from seeping into the layers beneath. Zippered underarm vents beneath our arms let us cool down fast while we're hiking, and the adjustable hem seals out the wind as we climb toward the summit.