The Montane Fast Alpine 40 Litre Backpack has all of the features you would expect from a mountaineering and climbing focussed pack. Constructed with fabrics for their durability and expected conditions of use. The main body is Raptor Rip stop 420D while the base is Raptor Endurance 420D an area prone to damage. The harness has been designed using Alpine fabric, a blend of nylon and elastane for ease of wear which also helps prevent shell damage when you wear it with a waterproof jacket.