Alpinestars S-MX Plus racing boot which raises performance and safety to new and unmatched levels with its innovative design, structural protection and comfort.Features: Contoured shin plate protector is injected with high modulus PU for superior impact and abrasion resistance U shaped calf protector is impact resistant and protects the ankle and calf area. Additional protection is provided by the top recessed buckle structure Interchangeable bi-injected PU toe sliders with snap-in assembly Wide and ventilated heel counter extends to the ankles and is combined with a shock absorbing padded insert and self-molding foam ankle protectors Replaceable sliders are positioned in the back and external section of the heel to allow the boot to slide and absorb shocks Injected PU material extended to the to area Large instep flex zone for maximum comfort and flexibility Lorica and leather upper Sole has been designed for improved feeling between the rider's foot and the pegs of the motorcycle Instep speed lacing closure and a unique lateral zipper Replaceable ratchet buckle closure on the calf features a hidden strap for security and is integrated with a calf slider Synthetic forefoot lining laminated with open cell foam. Highly breathable lining on ankle and leg areas Alpinestars anatomical and replaceable countered footbed provides arch support and forefoot pedal feeling