Birkenstock Madrid. Single strap with adjustable buckle. NOT the Big buckle version. Black. Size: EU 38 / US 7-7.5. Excellent used condition. Worn only once indoors to see if I liked them. Upper is Birko-Flor, the skin-friendly, tear-resistant and easy-to-care-for synthetic material made by Birkenstock. Insole is natural sueded leather and footbed is the traditional Birkenstock cork. Outsole is EVA. Box is a little torn, but will be included.