The Gizeh - NARROW FIT The fine construction of the Gizeh thong is specifically developed for the deep footbed, and corresponds perfectly to the anatomy of the foot. The Birkenstock thong styles guarantee a perfect fit and naturally surrounds the toes and guides them back to their natural position which are often constricted by formal dress shoes. Premium Materials Every pair of Birkenstocks is made from the highest quality materials. Birko-Flor Upper / Classic Footbed - Suede Lined Birko-Flor is the Birkenstock trade marked synthetic leather. It is a skin friendly, easy care fabric. Clean with a damp cloth. The essence of all our shoe models is the original BIRKENSTOCK footbed, which is inspired by the natural imprint of a foot in the sand and feels just like walking barefoot. Its anatomical shape ideally supports the natural walking action of your foot. Your feet, joints and back are protected. At the same time, your foot and leg muscles are exercised, and your health and well-being benefit as a result.