Nubuck Leather Upper Our top-grain leather is sanded on the outside to give it a slight nap with a velvet-like feel. This leather upper is extremely durable, while offering a shorter and more comfortable break-in period. GORE-TEX (GTX) 100% waterproof and breathable, GORE-TEX liners ensure that no water gets in, while allowing sweat and moisture to get out. Triple Stitched Hyper-strong thread is used to triple stitch our toughest boots. 400G Thinsulate Ultra Insulation High-performance insulation that keeps you warm in the snow and rain without weighing you down. Electrical Hazard (EH) Protection Meets or exceeds ASTM F2892-11 EH. Electrical hazard (EH) footwear is manufactured with non-conductive electrical shock resistant soles and heels. Composite Toe (NMT) Our composite toe is non-metallic, does not transmit heat or cold, nor will it set off metal detectors. As expected, it meets or exceeds ASTM F2413-11 M I/75 C/75 EH standards. Quarry Midsole Upgraded the midsole to a single, solid piece for increased longevity Vibram® Quarry Fire & Ice Outsole For superior traction in extreme cold and hot environments, this exclusive outsole features a 90º heel, an oil- and slip- resistant rubber compound, and a non-linear lug pattern for superior traction and debris release. Stitchdown Construction Handcrafted to provide a wider platform, our legendary stitchdown construction offers increased stability underfoot. Many of our stitchdown boots can be recrafted. How It Fits The 610 is our most universal last and can be worn by all foot shapes and sizes. It provides a snug fit through the heel while allowing ample toe room for most versatile fit. This allows more support and side-to-side movement. Recraftable Extend the life of your boot with our recrafting services. This boot is eligible for a number of paid services, including part replacement, leather care and restitching. See our Recrafting page.