Arc'teryx Chilcotin 20 Backpack Design promotes stability by wrapping around the body and pulling the mass close N210r-HT fabric is lightweight, durable, and coated to resist water and stains Mesh back panel is hydrophobic and promotes air flow. Foam offers comfort and reduces heat build up Monofilament mesh exterior / Spacermesh interior on shoulder straps dries quickly and offers ventilation Highly air permeable shoulder straps use Aeroform monofilament mesh and Spacermesh HD promotes air flow and comfort