MEPHISTO HELENA PERF | Women Cork Sandals. Perforated, this insole is a must-have for a relaxed summer. The unique SOFT-AIR technology integrated into the midsole guarantees fatigue-free walking. AIR-RELAX technology respects the anatomy of the foot to prevent arch collapse. The adjustable buckle on the instep provides an excellent fit. This women's metallic finger crotch is made of metallic-effect leather.