The Bilbao two-strap sandal combines the anatomically shaped design of the original BIRKENSTOCK footbed with an additional latex heel cushion and an air-cushioned PU sole. Anatomically shaped PU footbed Upper: Birko-Flor (synthetic compound) Footbed lining: suede Sole: PU (polyurethane) outsole that is resistant to oil and grease Two straps with adjustable metal pin buckles Non-Marking Sole