For the greatest comfort, we recommend wearing your new Vionic footwear for just a few hours for the first few days to allow your feet to adjust to the new level of orthotic comfort and support. Updated to provide the most secure fit with a functional buckle for adjustability across the vamp. Leather uppers. Firm yet flexible, removable EVA orthotic insert. Rubber outsole with patterned tread for improved traction. Biomechanically designed to hug your arches, FMT Technology helps support natural alignment from the ground up.