Birkenstock Madrid Sandal in “Purple Fog.” Worn only once - they’re just slightly small for me. Birkenstock size 37, which is roughly a 6.5/7 in US sizes. The original BIRKENSTOCK Sandal. A strap, a buckle, and a contoured cork footbed are masterfully combined to create the Madrid. The upper is made from the skin-friendly, hard-wearing synthetic material Birko-Flor®. Anatomically shaped cork-latex footbed Upper: Birko-Flor® Footbed lining: suede Sole: EVA Details: one strap with an individually adjustable metal pin buckle Made in Germany