The Naot Ostro has a padded heel cup & instep for ultimate comfort. This style has padded technical lining for comfort, warmth & moisture absorption. Naot's removable, anatomic cork & latex footbed is wrapped in microfiber & leather and molds to the shape of the foot with wear. The Aura Collection features a 1.5" polyurethane sole with a metal shank which is extremely lightweight, durable & abrasive to prevent slipping. This collection uses a hand-sewn stroble construction making it strong and extremely flexible.