Montane mens air jacket black lightweight breathable and versatile 3 layer mountain shell description constructed to deliver year round mountain weather protection the air jacket utilises new pertex shield ap fabric to achieve breathability durability and waterproofness with a hydrostatic head of 20 000mm and weighing just 350g it is a lightweight no compromise shell that will protect you in the lake district or during heavy downpours in the scottish cairngorms quick features