Bio Barracuda slipper made of ocher wool and polyester. Anatomic insole made of soft cork and covered with beige synthetic fur. TR rubber sole with ocher waves. Outer material: 90% wool and 10% polyester felt Insole: synthetic Outsole: TR The insole we use to make the slipper is anatomic, being a little softer than other types of footwear. If you hesitate between two sizes, we recommend that you choose the smaller one.