Why They're CoolI've never experienced a more comfortable hike in boots capable of carrying 40-pound backpacking loads. The trick? A softer insert embedded in the heel of a dual-density polyurethane midsole keeps things pillowy, while a polyurethane heel cup and full-length thermoplastic shank do their share, adding the rigidity needed for serious hauling. » Multidirectional lugs on the Vibram outsoles kept up the traction no matter which way the trail tilted. » Unseasonable Arizona rains allowed me to test the Gore-Tex booties in a muddy wash. My dogs remained bone-dry.Hmmm . . .As an inevitable corollary of the soft ride, support collapses quickly in the rough, despite the high all-nubuck uppers. I felt unstable bushwhacking with a heavy load.