The PAM 653 looks very much the part of your typical Panerai. It has a deep black dial and a full complement of those slightly bubbly Arabic numerals for the hours, rendered in a golden hue that is meant to look well-aged. The PAM 654, on the other hand, has a bright, ivory-colored dial with luminous dots to mark the hours and batons at 12 and six o’clock (double and single, respectively). The result is a pair of watches that, while technically identical, look completely different.