There is simply no better way to measure the effectiveness of a pack design than to send it out on thru hikes. Over the course of 2,000+ miles and an average of five to six months, day in, day out, loaded and unloaded, jostled and dragged, and exposed to the elements, one of these long walks is going to tell you the truth. Every carefully considered feature fought for its right to remain, leaving only the essentials required for an efficient, comfortable, adaptable, and dependable travel companion. Thru hiking is hard enough. Let the Unbound 40 carry some of the weight.