Part of our tried-and-true Tide Heritage Collection, Casandra has a feminine perforation and all-kinds of color options. Proven to effectively alleviate heel pain.* Uppers: Leather. Lightweight, flexible medium-density EVA midsole absorbs shock, reducing stress on feet, ankles and knees. Vionic Technology is biomechanically designed to hug your arches and support your feet in comfort. Vionic sandals' built-in orthotic is shown to be effective in helping to treat heel pain (plantar fasciitis). Outsole: Durable Rubber. Received APMA Seal of Acceptance.