Vibram FiveFingers is relaunching the KSO, their most successful FiveFinger ever! When you're scrambling up a rocky bluff or bounding along a river bank, the last thing you want is gravel and grit seeping in to your FiveFingers. So why now Keep Stuff Out! The KSO features a thin, abrasion resistant stretch polyamide and breathable stretch mesh that wraps your entire foot to do just that! A single hook and loop closure helps secure the fit. Non Marking XS Trek performance rubber soles are razor siped for a sure grip.