Army

When in 1968 the Swiss Army's combat diver corps chose the SUB 300T as official issue, it commissioned a modified version designed for underwater operations requiring maximum stealth: a steel case put through an oxidation process that turned it fully black, eliminating any reflection that could give away the diver's position. Between 1969 and 1975 around 146 pieces were delivered to a unit that, operating covertly, kept a low profile for decades even about the very existence of this watch, officially acknowledged as "Army" only much later.

The original piece retained the technical layout of the SUB 300T Conquistador — cushion case, unidirectional rotating bezel with no-decompression tables, helium valve — but with a manual-winding mechanical movement, a Hesalite crystal more shock-resistant than the mineral crystal of the era, and a solid steel caseback bearing no markings that could identify its military origin. For years the original pieces remained among the rarest and most sought-after in Doxa's entire production, practically unobtainable on the collector's market precisely because of the extremely limited run and the covert nature of their issue.

In 2022 Doxa revived the model with a reissue made in collaboration with retail chain Watches of Switzerland, limited to 100 pieces: the case and bezel are now in matte black ceramic rather than oxidized steel, the movement becomes a high-frequency automatic with COSC chronometer certification, the crystal switches to sapphire and the caseback to titanium alloy, while the indices receive a Super-LumiNova luminescent treatment absent from the original piece. The result is an explicitly modern tribute to a watch that, for most of its history, the public did not even know existed.