MADRID BF by BIRKENSTOCK is an iconic single strap slide that was the first BIRKENSTOCK model created, and has remained mostly unchanged since with its minimal design and exceptional comfort. MADRID features a natural cork sole, adjustable strap with buckle, an EVA sole and an anatomically moulded footbed designed to guide the foot to its natural position. The BF stands for Birko-Flor, which is one of BIRKENSTOCK's high quality synthetic alternatives to leather that is exceptionally durable and easy to clean, and has a smooth leather like finish. Product care: Please note, water can damage the cork and dissolve the glue/sealant. If your shoes get wet, dry them slowly and away from direct heat.