From Vibram FiveFingers' new Max Feel category, the KSO EVO features a reinforced upper, speed laces, and a zig zag patterned sole for grip and flexibility in all directions. . 0 heel to toe drop for barefoot benefits maximum sole thickness: 4.7 mm. Thin, flexible sole and individual toe pockets allow the foot to curl and flex as nature intended. 2 mm EVA insole with antimicrobial Drilex sockliner. Vibram XS Trek rubber compound outsole. Serrated blade lug design provides grip and flexibility in all directions. Reinforced polyester mesh upper for breathability. Lightly padded tongue for comfort. Speed lace system for easy entry. Machine wash cold air dry away from heat sources. Please consult the Size Chart for important sizing and fit information.