On small to medium backpacks that are at home in easier terrain we go for maximum ventilation. The heart of the Aircomfort systems – tested and proven for decades – is its flexible spring steel frame. It is extremely durable, provides stable tension for the airy back mesh and creates the ventilation space between pack and wearer’s back for the moist, warm air to dissipate. 1984 deuter invented & patented the first mesh back system worldwide.