Fizik m4b mtb spd shoeswith fiziks proven quality and clinical engineering these m4b mtb shoes have been made with only the highest grade technologies available tackle any mtb race in these lightweight stiff and trail resilient performers mtb shoes with carbon comfortm4b offers a superior blend of comfort performance and versatility this lightweight mtb shoe is all mountain tough and resilient yet nimble and agile for trail or cross country rides the light tough carbon reinforced sole