Birkenstock, rio, silver, last pair size 25 over many generations, the birkenstock company has gathered extensive knowledge in the area of foot health. This knowledge and experience is the foundation of their proven, high quality birkenstock sandals and shoes established 243 years ago, by johann adam birkenstock in langenberg, germany. Birkenstocks are constructed in layers to help the shoe mould to your foot. An eva outsole to aid flexibility, lower jute layer provides stability, cork latex core provides comfort and support, the upper jute layer absorbs moisture and finally the suede leather lining ensures optimum climate for your feet. Other features include: footbed edge: elevated to protect the toes toe bar: encourages natural gripping motion cross arch support: maintains the natural position of the metatarsal arch inner & outer longitudinal arch support: maintains the natural positioning of the medial and lateral arch deep heel cup: provides firm foot hold and even weight distribution.