S-MX 4 Boots Boot is a hybrid of high-performance race technology and everyday street riding functionality Wide-fitting foot shape design for maximum comfort Durable microfiber and injected PU construction guard shields the shin, ankle, calf, toe and heel from impacts Innovative air vents at the shin, calf, heel and forefoot are covered with specially-designed mesh that has a waterproof membrane that lets the foot breathe in warm weather while keeping moisture out