The Radiomir is the first watch prototyped in 1936 by Officine Panerai. It was distinguished by the structure of its iconic cushion shape which ensured a particularly high degree of water-resistance through its conical screw-down winding crown and screw back, while the use of Radiomir, a luminous paint based on zinc sulphide, mesothorium and radium bromide, gave the dial maximum visibility even in the hardest conditions. This historic case had thin wire loop strap attachments welded to it.