From the inside out—200g of PrimaLoft® Bio™ insulation and a B-DRY waterproof membrane—the Sphinx Mid is at home in ice-laden mountain towns. Featuring waterproof oiled nubuck leather, recycled components, and a Vibram Arctic Grip A.T. sole made of Vibram XS Trek. *This style runs small. Please order up a half size. Insoles made with Bloom Algae technology use sustainable algae biomass without compromising durability or comfort. Molded to match the specific shape and construction of every pair we make, this purpose-designed technology delivers the kind of fit, feel and performance that’s unmatched in the industry.