Size: 36 euro Only worn a few times. The BIRKENSTOCK Madrid is the oldest member of the family of models, making it a veritable classic. Launched as a “gymnastics sandal” half a century ago, this simple single-strap model has gone on to become a firm fashion favorite. Anatomically shaped cork-latex footbed Fabrication: Manmade Footbed lining: Manmade Footbed: Classic contoured cork footbed with deep heel cup, arch support and toe bar Sole: Manmade EVA Details: strap with an individually adjustable metal pin buckle.