Boot upper incorporates an innovative front and rear bellows and rear calf zone for higher levels of flexibility, Boot upper is constructed from microfiber for durability and abrasion resistance, Ergonomic forefoot streamlining enables greater control of the bike's controls and provides a superior, wide-ranging foot profile for excellent fit and comfort, Alpinestars innovative TPU lateral ankle brace provides a biomechanical support between the lateral top calf/shin and ankle and provides improved structural integrity, protection against impact shocks, repeated abrasion resistance and flex support, Air vents on the heel counter and shin plate plus breathable mesh inserts improve comfort and reduce fatigue on the ride (vented boot styles only), High modulus TPU-injected shin guard, calf protector, heel counter, shift pad, ankle brace and toe slider for improved shock protection and durability, Double-density ankle protector on the medial side, layered under the upper, offers protective performance in key areas, Integrated, replaceable bi-injected TPU slider features a new easy-screw fixing concept for quicker, easier replacement, Innovative instep and Achilles accordion flex zone construction for superior comfort, extension, control and support, Internal insole with shake reinforcement integrated for support to the arch area and foot protection, Medial side entry opening/closure system features elastic-mounted zipper with wide hook-and-loop closure for flexibility and a secure fit, Aperture opening is large to promote easy in/out of the boot, Internal toe box protection is layered under the upper for durability, improved feel and performance, Breathable textile interior lining features anti-sliding suede reinforcement on the heel area to help keep the foot in position while riding, Removable anatomic footbed includes EVA and stretch fabric for performance, comfort and support, Rubber compound sole promotes improved feel and grip, water dispersion and durability, Drystar® version has Alpinestars waterproof, breathable liner, which provides excellent all-weather performance