The inside of the shoes is covered with thick eco-fur..19-12/20-12,5/21-13/22-13,5/23-14,5/24-15/25-15,5/26-16,5/27-17/28-17,5/29-18/30-18,5/31-19/32-19,5/33-20,5/34-21/35-21,5/36-22,5cm On cold days it is worth taking care of warm shoes for our children.