Upper: Natural leather
Natural leather can be recognized by its untreated surface. BIRKENSTOCK purposely does not treat surface grains and other characteristic features. BIRKENSTOCK uses sturdy leather with a thickness of 2.8 to 3.2 millimeters as upper material.
Microfibers are a very fine synthetic fibers that are extremely soft and shape-retentive. Because they are free of animal products they are used as the covering material for the lining of footbeds in vegan products, among other things.