Women's Madrid Big Buckle (Cognac)A strap, a buckle and a contoured cork footbed are masterfully combined to create the original Birkenstock sandal the Madrid. An iconic slide with amplified buckle accent. Shown in oiled nubuck leather. Upper material: Oiled leather Oiled leather is one of our favourite types of leather. Its oily waxed surface makes for a unique colour effect and develops a beautiful patina. The oily finish of our natural leather products results in colour variation,