The modern thong sandal from Birkenstock. The Gizeh is an addictive classic with signature support and a refined, minimalist style.These thong sandals "work" the feet, which trains the muscles in your legs while boosting circulation.The upper is made from the skin-friendly, hard-wearing synthetic material Birko-Flor in a sophisticated nubuck look which boasts a texture and color that could almost be mistaken for real leather.