The Birkenstock Women's Mayari Birkibuc Casual Sandals features a cross strap with a toe loop with adjustable straps to secure your feet. These flip-flops are textured finish upper that feels like velvety nubuck is known as Birkibuc. It's made of acrylic and polyamide felt fibers. The original Birkenstock footbed has a deep heel cup that keeps the foot's natural padding under the heel to provide stability. | Birkenstock Women's Mayari Flip Flops