Based on the boots of the champions as Tony Cairoli, Sidi developped a new offroad/supermotard boot, the X-3 SRS. The Sole Replacement System (SRS) makes sure that the boot switch really easy from an offroad boot, to a supermoto boot or even an adventure boot. features Lined with air Teflon mesh & Cambrelle Upper in leather & Microfiber material Fully replaceable & adjustable spare parts Micro & replaceable Adjustable buckles Dual Flex System New adjustable system of the area between the protective calf-exaust & thefront of the boot to allow a rider with a wider calf to be very comfortable. Nylon Inner sole Sole Replacement System Rubber SRS MX-Sole SRSâ stands for â Sole Replacement Systemâ making it possible to replace the soles. MX Sole Enduro Sole Supermoto Sole (2-colors) This item cannot be shipped to the United States & Canada.