The Sidi Mag-1 Boots feature an innovative internal brace system constructed from carbon fiber for the ultimate in support and light weight design. The Mag-1 Boots weigh in at 4.4 pounds each, or 17% less than the Vortice boots. An all new Micrometric Tecno 3 magnetic closure system makes adjustments quick and easy and the internal brace system provides ankle stability and flexibility. Features: Arch and Achilles areas are covered with Sidi’s exclusive elastic textile and injection molded polyurethane comfort panels Arch area utilizes two TPU bands next to the TECNO-3 Magnetic closures, for a maximum support and wrap of the arches Asymmetric and shaped shock absorbing heel cup, smooth and flat inside for more adherence with the bike, with shock absorbing system in the back and outside The shell and the shock absorbing system are replaceable through a screw and an interlocking system Nylon inner sole with removable arch support pad Replaceable external shin, heel and toe sliders Nylon inner sole Dual compound sole High stress areas are double stitched TPU shift pad Perforated, Teflon treated nylon inner lining with Cambrelle lining in the toe area Recessed screws used to attach replaceable parts so as to not damage bike Toe slider made from nylon reinforced with fiberglass Toe Slider features new air intake and alloy insert Adjustable calf on the Sidi Mag-1 Boots can accommodate riders with up to an 15-inch calf diameter when measured 11.5-inches up from the bottom of the heel