Omega Seamaster 300

In 1957, Omega released a trio of sports watches: the Speedmaster, the Railmaster, and the Seamaster 300.

In 1964, Omega unveiled an entirely new design for the Seamaster 300 under the reference numbers 165.024 (no-date) and 166.024 (date-displaying). The case diameter of the Seamaster 300 increased from 39mm to 41mm, and its signature thin bezel was replaced by a much thicker one with a wider insert, that featured individual minute markings the entire way around it.