While most Birkenstock shoes are not vegan, Birkenstock does make several vegan options. Normally, Birkenstock shoes have a suede-lined insole made of animal skin; this non-vegan insole is usually printed with a yellow or blue ink, and has a leather symbol with the words "BRAND SOHLE LEDER," meaning "LEATHER INSOLE" in German. Shoes made with a synthetic Birko-Flor or Birkibuc uppers still have suede leather insoles unless otherwise explicitly stated in the product description. However, Birkenstock does make vegan-friendly versions of some of their styles for the UK market complete with vegan-friendly nonleather insoles. Vegan Birkenstock insoles are usually printed with a black ink but will never contain the words "BRAND SOHLE LEDER" or the leather symbol. Also, Birkenstock's waterproof line and many of their professional clogs are made with polyurethane, EVA, or Alpro foam, making them vegan-friendly.