The best selling Birkenstock Arizona sandal has two Birko-Flor buckle fastening straps for a secure custom fit. The benefit of wearing the Birkenstock Birko-Flor material is that it is skin-friendly, has a soft backing and designed not to rub. The unique anatomically shaped natural cork footbed is shock absorbing, cushioned, extremely supportive and over time contours to the shape of your foot. The EVA outsole is also very lightweight, cushioned and super flexible. Birko-Flor upper Anatomically shaped cork footbed Footbed lining: suede Sole: EVA Regular Fit Buckle fastenings New without tags, never worn. Non smoking, no pets. purchased in Germany at a Birkenstock store. Please let me know if you need additional pictures or information.