Furs are intended to represent animal skins, and are of two fixed colours. DrawShield supports the following heraldic furs:
Ermine, erminois, counter-ermine, erminites, pean
Potent, counter-potent, potent-counter-potent
Vair, counter-vair, vair-en-point, vair-in-pale
There are treatments Vairy, ermined and potenty which have the same appearance as the corresponding fur but allow you to specify the two colours.