Sidi Crossfire SRS boots are a high-tech boot that will stand up to the use and abuse and continue to offer superior protection and comfort. It all starts with an understanding of what it takes to develop a boot that has the best form and function and the Sidi Crossfire SRS boots have nailed it. To start, the Crossfire SRS have an external Dual Flex system to allow for fluid movement front and back, but extremely rigid side to side movement. Sidi designed the Crossfire SRS boots realizing riders will be putting these boots through the stresses involved with competitive and aggressive riding by making the high wear parts to be replaceable. The soles on the Sidi Crossfire SRS are the simplest replacement system on the market. With a standard Phillips screw driver the sole comes off for easy replacement. Sidi offers multiple types of soles to match your needs. To continue raising the bar on safety, Sidi uses a composite insole on the Crossfire SRS boots which doesnt deteriorate like a steel shank can. Sidi also includes a removable arch support to match the riders foot type. No rider is the same, which is why Sidi designed the calf of the Crossfire SRS boots to adjust, making the boot fit better for increased protection and comfort. Sidi uses their own Technomicro on the Crossfire SRS boots. Technomicro is a composite microfiber material created from strands that are so fine, each one is less than one thousandth the thickness of silk. The cam-lock buckles on the Sidi Crossfire SRS are independent providing less resistance and better range of motion. The cam-lock buckles are attached to straps with position memory, making adjusting the strap length a one-time thing. The Crossfire SRS boots are lined with a Cambrelle material to keep your feet nice and cozy. Sidi took advantage of their high-tech design to eliminate the need for an inner booty on the Crossfire SRS boots. By eliminating the inner booty the Crossfire SRS boots are able to shave weight and keep a slender body for easier control and better feedback.