La Sportiva - Makalu (Natural) - Mens: Made for mountaineering and heavy backpacking. Rollerball hardware and a locking D-ring allow independent fit in the lower and upper portions of the boot. Features an MPE sole (MPE stands for Mountaineering Performance Evolution): This proprietary sole features a dual-density SBR design, an SBR Aircushion, self-cleaning lugs, and automatic crampon compatibility. MPE Sole is crampon compatible, deep lugged and tough as nails for years of service in the harshest conditions. Features a 3mm Idro-Perwanger leather with rubber toe rand for durability and protection in all mountaineering applications. 8mm Mtnflex insole with a 1.5mm Dacromet-coated full steel shank. Weight: 4 lbs. 5 oz.