The back of this card is an early example of a divided back -- the space is unequally divided between address and message, which marks a transition from the older cards, which devoted the entire back to the address in accordance with postal regulations, to modern cards which split the real estate even between address and message. The "Post Card" label on this series of Art Manufacturing cards is in a heavy black-letter typefont, and the stamp box is outlined in a dash-and-dots rule. Here's a close-up: Front of card