Vibram Fivefingers Spyridon MR - Men'sFor the minimalist runner with power and perseverance, the Vibram Fivefingers Spyridon MR, short for Mud Runner, is a shoe designed with you in mind. Take on a mud obstacle course or trail race wearing this lightweight minimalist shoe crafted specifically for the rough and rugged. The upper is made with polyester fabric for a secure fit and durability, with a molded 3D cocoon nylon mesh that adds a "rock block" effect that disperses impact over a wider area. A Vibram XS Trek compound uses a 360º lug design for solid grip in all directions– so this shoe is sure to outlast whatever mess you get yourself into. Wt. 7.8 oz.