Just a tad softer than the Instinct, Scarpa tune up the slipper design with a single strap and Vibram XS Edge rubber to resist deformation when standing on micro-flakes and edges. The Instinct VS spans the performance arc from slabby boulder problems to overhanging gym routes. Sensitivity, with just enough power from the Bi-Tension randing for standing on dimes; these do it all. Bi-TensionBasically, a reverse slingshot rand that's anchored under the critical toe area and connects directly to the heel rand, only there's nothing basic about it. The patent-pending system actively pulls power from the toes, rather than cramming your toes painfully forward, giving immediate performance with less tension. And that means less rubber, making your shoes lighter, more sensitive and more reactive. Vibram XS EdgeDeveloped to provide maximum edging support, the VIBRAM XS Edge compound delivers excellent pure grip while adding improved firmness for the most challenging edging moves. Thanks to an improved resistance to plastic distortion, it keeps its shape even after hours of use, maintains consistent feel in both hot and cold temperatures, and is formulated for improved durability. Vibram XS Grip² This sole is used where pure grip is needed! Shoes with this sole are therefore indispensable for competitions or in overhanging routes.