Carbon Fiber Brace system First things of notice is that the Mag-1 has no visual brace system. Sidi Integrated a carbon-fiber brace in the boot itself. This brace allows excellent flex movement front-to-back while being firm side-to-side. The rear-upper features a soft red TPU-plastic to prevent the system pushing in your calf. Tecno-3 Magnetic closure system The newly fitted closure system called " Tecno-3 Magnetic" makes sure the boot will perfectly fit by its precise adjusting. It is quick & easy to use due to the magnetic closure, helping you close the boot with one hand only. The magnets will stick on the boot in order to keep the closure in place. The boot folds together, which makes a zipper superfluous. A-Symmetric ankels & a zipless closure The ankles of the boot are smooth & flat inside for more adherence with the bike & feature a replaceable shock absorbing system in the back & outside. The boot is made from synthetic leather & is triple-stitched on the high-stress areas. The arch & Achilles areas are covered with Sidi’s exclusive elastic textile & injection molded polyurethane comfort panels The Calf of the Mag-1 can accommodate riders with up to an 35 cm calf diameter The inner lining features a membrane made from Teflon & nylon which folds around the calf & ankles. The lower part of the boot has a Cambrelle lining. The Toe slider is made from nylon reinforced with fiberglass & features an air intake & alloy insert. The Calf of the Mag-1 can accommodate riders with up to an 35 cm calf diameter when measured 25 cm up from the bottom of the heel. Features Upper in Technomicro- Microfibre Lined with air Teflon Mesh Integrated Brace-system Tecno-3 magnetic closure system Shock Absorbing heel cup Adjustable Calf & zipless closure Lightweight Most parts of the boot can be replaced This item cannot be shipped to the United States & Canada.