The sole is extremely abrasion-resistant. The raised toe bar is an integral part of the design of all BIRKENSTOCK sandals and clogs. It encourages the natural gripping motion of your feet, thus exercising your toes and supporting the flow of blood. The deep heel cup stabilizes and supports the heel – for a natural walking experience. The Birkenstock Unisex Arizona Birko-Flor Sandals come with two straps and an EVA sole. The Birko-Flor upper is made of easy-to-care-for and hygienic PVC, which has been lined on the inside with a soft, breathable layer of fleece. This high-quality material is very gentle on the skin and it’s comfortable while also being very durable. The flexible leather lining, which is gentle on the skin, nestles up softly against your foot and adjusts to its contour. The open-pored and thus very breathable surface makes for a comfortable foot climate, even during more strenuous physical activity. EVA (Ethylene Vinyl Acetate) is a high-quality, very light, elastic material with extremely good cushioning. It smoothes out slight irregularities in the floor and ensures that every step is softly cushioned. The sole is extremely abrasion-resistant. The raised toe bar is an integral part of the design of all BIRKENSTOCK sandals and clogs. It encourages the natural gripping motion of your feet, thus exercising your toes and supporting the flow of blood. The deep heel cup stabilizes and supports the heel – for a natural walking experience.