Birkenstock Unisex Arizona Caribou Nubuck Sandals - 44 N EU / 11-11.5 C(N) US birko-flor Upper material: Suede - Thick and supple leathers without additional dyes to keep the leather breathable durable and comfortable. Footbed: The original Birkenstock footbed - Featuring pronounced arch support deep heel cup and roomy toe box. Footbed molds and shapes to your foot. Sole material: EVA - Flexible lightweight durable and shock absorbing.