The present watch is a rare example in an extremly good original condition of a reference 5512. Featuring pointed crown guards, a black lacquer dial with gilt printing, and an "underline dial".
Rolex indicated the use of tritium by producing some "underline dials", characterized by a small silvered line under the designation Submariner or under the word Oyster Perpetual. Such dials were used between 1960 and 1964, and as of 1964, the designation "Swiss T<25" was added to the bottom of the dial, referring to Swiss made watches that contained a quantity of tritium emitting less than 925 MBq (megabequerel) or 25 mCI (milliCurie).
References 5512 was introduced in 1959 and produced until the late 1970's. Pointed crown guards can only be found in the first few years of production. Lovingly referred to as "cornino" by Italian watch enthusiasts, the ends of these crown guards are much thinner, almost tapering to a point, compared with the more rounded crown guards of later standard Rolex production.