Extreme durability, big-load support, ankle protection, and breathable water resistance. That’s what one tester, an Alaska-based NOLS instructor, says she looks for in a summer mountaineering boot. This model has all of those essentials, plus minimal break-in—rare in such a burly boot—thanks to flex points provided by cut-outs in the one-piece leather upper.
That upper is made of 2.8-mm-thick, silicon-impregnated leather from Italy’s 230-year-old Perwanger Tannery. It’s armor-tough and functionally waterproof. The upper has no membrane, making it exceptionally breathable. Testers reported dry feet in standard wet-hiking conditions—even stomping up a stream in New York’s Adirondacks (the boots will eventually leak if submerged for a long period). A honeycomb grid in the midsole creates shock-absorbing air pockets that didn’t break down under the heaviest pounding, like the EVA used in lighter boots will, and it’s covered with a high-density nylon plate that provides torsional stability.
“It’s plenty stiff for big-load support and crampon use,” says a tester, “but it has enough rocker for striding on long, flat sections of trail.” Testers praised the under-toe climbing platform for its no-give edging on technical step-ups. And unlike with some big boots, testers reported no shin-bang (thanks to tongue padding) and no toe-bang (due to D-ring locking laces that secure heels and fine-tune fit). Verdict: Summit counters, better pack a calculator. $270; 4 lbs.; m’s 38-48, w’s 36-43Exum Pro is a radical hybrid of running shoe technology in an approach shoe design.