MEPHISTO HELISA | Women Cork Sandals Dark Blue Leather Nubuck. This marvellously lightweight mule, with its relaxed look, promotes a perfect sensation of well-being. The SOFT-AIR cork midsole minimises impact for a gentle, effortless walk. The AIR-RELAX technology respects the anatomy of the foot to prevent fallen arches. Adjustable straps with buckle fastening.