Calavera Walnut Bison Work ApronCalvera Tool Works likes to take a few liberties with the Walnut Work Aprons, so you can expect that no two are the same and that yours will start off with a character very much its own. Some are darker, some are lighter and some even feature the hide's original brand or scars from pesky varmints or barbed wire. They are designed for an easy break in for many years of comfortable wear. Main Panel: Hand dyed Walnut Bison Thickness: 4 4. 5oz whole hide