“Directly descended” from a prototype created for Italian naval frogmen in 1936, the Radiomir ‘California 3 Days’ is unusual in that it features both Arabic and Roman numerals on its dial.

The 47mm ‘cushion’ case houses Panerai’s in-house P.3000 calibre movement - hand-wound but having an impressive three-day (hence the name) reserve of power.

As a Radiomir model it features the characteristic thin wire strap attachments, a conical crown and a simple dial designed to be highly legible underwater.

It carries the unique face believed to be of a type first fitted to the then Florence-based manufacturer’s diving watches.

The sophisticated tobacco and brown dial also carries the ‘OP’ logo, the inscription ‘California’ engraved on the case at 12 o’clock and a small date-window at three o’clock. The strap is the characteristic thick brown leather much loved by Panerai collectors, and made in the style of the very early prototype divers’ watches.

Panerai Radiomir California 3 Days is part of the company’s Heritage Collection.

Photo: Panerai