Vionic Tide II Thong Sandals EVA midsole, TPR outsole sole A strip of patent leather lines the nylon upper of this classic flip flop. Podiatrist-designed- biomechanical orthotic footbed with deep heel cup helps support and realign the feet back to their natural position. Lightweight- flexible EVA midsole absorbs shock to reduce pressure on the feet- ankles and knees. Durable rubber outsole with geometric-patterned tread provides traction on a variety of surfaces. Clinically shown to help relieve common causes of plantar fasciitis- heel pain and knee pain- related to over pronation and flat feet. Has the American Podiatry Association Seal of Acceptance.