Birkenstock Arizona 2-Strap Cork Footbed (Women's) Mocha Birkibuc Sandals (37 M EU, US 6-6.5) Birkibuc upper: a synthetic, highly durable, affordable, and easy-to-clean materials that are also extremely soft next to the skin. 2-Strap Cork Footbed (Women's) Mocha Birkibuc Sandals (37 M EU, Fits US 6-6.5, Normal/Regular Width for Regular to Wide Feet) Footbed: The classic Birkenstock footbed - features pronounced arch support, a deep heel cup, and a roomy toe box. The footbed conforms to the shape of your foot. Sole material: EVA - flexible, lightweight, durable and shock absorbing. Finished with logo-engraved buckle closures for a perfect fit. Upper material: Birkibuc - a mix of Birko-Flor and Nubuk fibers.