Some features: Dual Flex System: The hinged, dual position, stitch-free upper is constructed from injection-molded plastic. With the exclusive Dual Flex system and the four floating independent straps the Crossfire can provide each rider with a personal fit no matter his body shape or if he uses knee braces or not. Adjustable Calf System: Sidi's exclusive, patented, adjustable calf system allows the rider to adjust the diameter of the Crossfire boot at the calf. This system, along with longer upper straps, allows the Crossfire boot to accommodate riders with larger calves easier than any other boot now available. The Crossfire can accommodate riders with up to a 22-inch calf diameter 14 inches above from the bottom of their heel. The inner plastic plate is made of two different materials; a rigid one to support the boot and a heat resistant one to protect the rider's leg from exhaust heat. All components of this system are fully replaceable and are available in a wide variety of colors. Heel Detail: Three extended ribs are featured at the back of the boot to assist the rider in making upshifts with his heel when starting a race. Rigid, shock resistant, anatomically shaped heel for maximum protection. Non-Bootie Designs: Sidi boots do not incorporate inner booties into their design, and for good reason. Booties make the design larger and cumbersome; add to the boot's thickness, which interferes with shifting, plus the inner booties retain body heat affecting the rider's performance and comfort. Buckles: Sidi's exclusive cam-lock buckle system is acknowledged as the finest system on the planet. It must be as most of Sidi's competitors have attempted to copy various aspects of it. The cam-lock buckle system incorporates a strap memory retention system. Adjust the straps once and they will be at the same position for every ride after that! No more readjusting for every ride or mid-day during a ride. Toe Areas: The tip of the toe on the Crossfire and Charger boots are covered with plastic to protect the base material and seems against abrasion from brush etc. Plastic shift and brake lever guards on the top of each foot area.