Rolex made for Officine Panerai Reference 6152
Following a decade of successful production of reference 3646, the Italian Navy requested an improved and updated version of their diver's wristwatch. Sometime in the mid 1940s, the new reference 6152 was presented, more solid and with increased water-resistance, its case made out of one massive block of steel and with wider, downturned lugs replacing the less solid wire lugs.
This upgraded model was entered under reference numbers 6152 and 6152/1, predominantly known as the "Luminor". This designation was derived from the luminous substance based on tritium used for the numerals and hands and for which Panerai obtained the patent in 1949. It replaced the previously used "Radiomir" mix developed between 1910 and 1915. Early examples of reference 6152 still feature the "Radiomir Panerai" signed dials dating from before the introduction of "Luminor". Most of the models were fitted with a crown protecting bridge, invented by Panerai as early as 1943 but patented only in 1956. Its main functions were protecting the crown from shocks, compressing the sealing gasket with the lever to make the watch water-resistant to a depth of 200 meters while allowing the winding of the movement even when submerged.
For the majority of reference 6152 production Panerai used exclusively cases and movements made by Rolex. These watches were "time only", e.g. showed only the hours and minutes. Later versions were fitted with the Angelus 8-day movement with the subsidiary seconds function to 9 o'clock, the cases were made locally.
Watches supplied to the frogmen, SLC torpedo riders and commandos of the Italian Naval Forces were requested to bear the designation "Marina Militare" on the dial. The present watch is from this series, furthermore bearing the engraved military marking "M.M. 050" for "Marina Militare" (Italian Naval forces) and the relevant unit number on the case back.
Other markings found on reference 6152 case backs include:
SMZ= somozzatori (divers)
M.M.= incursori della Marina (divers of the naval forces)
G.F. = somozzatori della Guardia di Finanza (divers of the Italian military police force under the authority of the Minister of Economy and Finance)
C.C. = somozzatori dei Carabinieri (divers of police forces)
V.F. = somozzatori dei vigili del fuoco (divers of the firefighters)