The KSO is arguably our most successful FiveFinger to date, mainly due to its versatility. When you're scrambling up a rocky bluff or bounding along a riverbank, the last thing you want is gravel and grit seeping into your FiveFingers. Product features: SOLE SPECS: Insole: Polyester Microfiber, Midsole: N/A, Rubber: 3.5 MM UPPER MATERIAL: Stretch Polyamide, Polyester, Hypalon(R) VEGAN Machine Wash Cold, Air Dry Please not box is ripped on the side from opening wrong.