The modern thong sandal from Birkenstock. The Gizeh is an iconic classic with signature support and a refined, minimalist style. Shown in Birko-Flor®. Birko-Flor is made of easy-to-care-for and hygienic PVC, which has been lined on the inside with a soft, breathable layer of fleece. This high-quality material is very gentle on the skin, and it's comfortable while also being very durable.