Cross frostbitten toes off your list of high-altitude worries: If these boots don't keep your feet warm, you shouldn't be up there. The soft inner boot of the 8001 is a removable, rubber-soled lace-up insulated with 200 grams of Thinsulate. It slips inside a heat-reflecting Kevlar outer boot that laces up and then cinches with a power strap around the comfortably soft cuff. A softshell- and neoprene-lined waterproof/breathable gaiter is welded to the outer boot to seal out the elements. Underfoot are three layers of protection: a grippy, snow-shedding Vibram sole, a fiberglass-reinforced nylon midsole with polyurethane crampon shelves for total rigidity, and a layer of EVA foam for cushioning.
It's not often that a multilayered mountaineering boot is called "nimble," but that's how one effusive mountaineer described the 8001 after a month of summits in Chile and Argentina. "When you're hypoxic, you stumble around," he wrote. "In this boot, you know where your feet are and you trip less, which reduces the klutz factor." Gripes: One tester complained that the zipper pressed uncomfortably against the shin after a multihour post-holing epic, and that multiple layers of lacing were hard to manage with frozen fingers. Best for medium-width feet. $850; 7 lbs. 12 oz. (size 11); men's 8-13; kayland.com