The Bitterroot GTX brings together the best attributes of the world’s leading midsole technologies. By skin-wrapping an EVA chassis in a TPU armor, for example, we obtain a combination of rigidity and cushioning that otherwise wouldn’t be possible. From the aggressively lugged Vibram Summit outsole, to the all-leather upper, the Bitterroot GTX represents the absolute state-of-the-art in rugged, backpacking boots. The Bitterroot GTX features the Vasque exclusive Vibram Summit sole, with a EVA foot cradle with protective TPU skin, PU heel cup with EVA shock pad, TPU torsion control chassis, and a Vasque Exclusive Vibram Summit rubber outsole. The boot feature Gore-Tex for durable waterproofing. Fit Profile: The Bitterroot GTX is built on the Summit last, a combination last that uses the Arc Tempo’s medium volume heel (designed to fit a wide range of shapes) with a straighter forepart. This last provides a positive heel lock pocket, excellent arch support, and rockered toe for less walking fatigue in stiffer boot.