A bar-code label has a combination of a plurality of narrower slots and a plurality of wider slots encoded to represent specific binary data containing information and/or instructions. The slotted bar-code is encoded on a rigid label member, such as a metal sheet. A bar-code encoding device used to encode the slotted bar-code has a pair of punches, one of which is adapted to form the narrower slots and the other of which is adapted to form the wider slots. Both of the punches are operated simultaneously whenever one of the narrower orwider slots is formed. The blank label is fed past one of the punches to form all of the narrower or wider slots before forming the rest of the wider or narrower slots with the other punch. The encoded label thus formed is suitable for use in painting or coating processes which would obscure a conventionally printed bar-code label.