Birko-Flor: Birkenstock's patented synthetic material that is very similar to leather. It can come in a variety of colours, prints and textures. It is made up of a smooth top layer and an inner layer that is extremely skin-friendly. Suede and Cork: (Birkenstock's anatomical insoles are made from: Suede, Cork, Latex and Jute). While suede guarantees a soft feel against the skin, the fusion of cork, latex and jute provides cushioning, stability, freshness and unparalleled comfort. EVA soles: (Ethylene vinyl acetate) High-quality synthetic material, lightweight and with unique cushioning properties.