These grisly tokens are made from the fingers of mages. Worn by mages, when the wearer would take damage the small bones crack instead.
This is another one I haven't play tested. Probably should be some price or cost to make it, but the roleplaying possibilities seem too good to pass up. Will your players stop to collect the fingers of the wizard they just slew? What will the townies think of your mage walking around like some crypt robber?
No thumbs. A foe does 8 points of damage, 8 bones snap irreparably. You could limit it to magical damage if you wanted.