The Sidi Crossfire 3 SRS boots are CE-approved with an ultra-durable Technomicro Microfibre upper lined with Cambrelle and air Teflon mesh for additional durability and comfort. The SRS dovetail sole with the innovative and patented interlocking system gives it the SRS title, and this has a flex system upper with an exclusive and patented flex system with a hyper-extension block. The micro-adjustable and replaceable buckle system gives the perfect custom and secure closure. Replaceable metatarsus inserts and rigid, shock-resistant, anatomically shaped heel cups give additional durability for increased impact resistance.