The Radiomir is Panerai's oldest (and, some argue, purest) design. Even at a glance, its rugged aesthetic and simple dial point to its origins as a military dive watch. One of the most distinctive features of the Radiomir is its fairly big cushion-shaped case, which was designed to accommodate a larger movement which at the time was required for better accuracy. It features large, easily legible luminescent numerals that helped divers navigate the murky depths. The cushion-case and large crown add to the practicality of the watch, as well as making it a design icon. While the Luminor might have more bells and whistles, the Radiomir is the watch that kickstarted Panerai's success today.