Sheepskin and Lambskin
The best, top-quality twin-faced sheepskin is used to make our slippers and boots.
Twin-faced means in essence the 'real sheepskin'. The hide side is tanned (oops, strains of Rolf Harris - but he's Australlian!) and the wool side is trimmed to 15mm all over so that it is comfortable at all pressure points.
Read more about sheepskin here (scroll down a long way!).