Birkenstock Women's Mayari Adjustable Toe Loop Cork Footbed Sandal Mocha 40 M EU Imported Birkenstock Women's Mayari Adjustable Toe Loop Cork Footbed Sandal. Premium Birko-flor upper with adjustable buckle closures to ensure easy on-and-off wear and a secure fit. Birko-flor is made of acrylic and polyamide felt fibers. Anatomically correct cork footbed, crafted from cork that is 100% renewable and sustainable, encourages foot health. 40 M (US Women's 9-9.5), Normal/Regular Width.