Birkenstock Women's Sydney Luxe Buckle Birko-Flor SandalSize Chart The BIRKENSTOCK Sydney proves that fashion and functionality can go hand in hand. With its two simple straps, its a real hit with women who want both high fashion and comfort. This sandal version has a silky sheen finish. The shiny, gently rounded padded buckles are especially eye catching. The upper is made from the skin friendly, hard wearing synthetic material Birko Flor. Anatomically shaped cork latex footbed Upper: Birko Flor Footbed