in the 1960's OMEGA made a series of movements internally , with NO PARTS outsourced from any other company, the gears, little screws, handset etc etc etc ... were all fabricated by OMEGA itself the series was called the 600 because they were made in 1960...
VINTAGE PLEXI back in the day ... 2 options were offered to customers to mount ... for the Seamaster 600 and the Omega Seamaster DeVille models Crystal part # - PZ5007 ..... NO date magnifier @ 31.6 mm diameter, acrylic with metal tension ring Crystal par...