The KSO is arguably our most successful FiveFinger to date, mainly due to its versatility. We added this back into the mix a few years back to celebrate the rebirth of a legend. 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. So why not Keep Stuff Out! The KSO has a snug fit, one of our most minimal sole constructions for maximum ground feel, and a breathable, quick drying upper.