The Birkobalance arch support is one of the classic arch supports from Birkenstock. They have been making this product for years and it adds firm but gentle support to a wide range of shoes including casual, dress and athletic shoes. Birkobalance arch supports are constructed from Birkocork™, Birkenstock's unique and durable blend of natural cork and nylon. The Birkocork is molded into a highly contoured arch support shell and covered, on the top with perforated leather. The perforations promote air flow and breathability.