Bio Genuins sandal made of synthetic material. Fastening to the instep. Anatomic sole made of soft cork andﾠtoasted sheepskin. The insole we use to manufacture Genuins is anatomical, being a little more loose than other types of footwear. If you have doubts between two sizes, we recommend you choose the smaller one.ﾠUpper material: synthetic Insole: leather Sole: XTR