Stainless steel Seamaster 300 automatic wristwatch. Made 1969

In 1955 Omega bought a small watch factory owned by and called Marc Favre, who had created an automatic calibre using a full rotor. In 1958 they produced the 552 calibre movement which was both shock absorbing and anti-magnetic with 24 jewels. 562 was the same watch but with a calendar function. The 565 (1965) came with a calendar function but also with rapid date corrector. The calibre 563 (1965) was produced for the American market and featured a calendar function but reduced to 17 jewels. The Calibre 560 was also for the American market; this was a 552 calibre reduced to 17 jewels 

OMEGA introduced a new numbering system in 1961 and the 165.014 marked the first use of the 6-digit case number system.  The 165.014 still housed a calibre 552 and had much the same look as previous variations but now sported new dial and hand combinations with a case size of 42mm.

Cases were made by two primary manufacturers, Huguenin Freres (HF) and Centrale Boötes and can be determined by the presence of small HF or CB stamps inside the case back.  Some later cases can be found bearing Piquerez markings.