213.30.42.40.01.001Ref

The 1957 OMEGA Automatic Seamaster 300 was promoted as a timepiece made for both professional and amateur divers, with water resistance to 200 metres, and was later described as the perfect accessory for professionals. Its '300' name came from performance that far surpassed the limits of contemporary test equipment, due to the crystal and crown; it housed calibre 28 SC-501, a matte black oxidized dial with Arabic quarter numerals, luminous triangular markers, radium-treated arrowhead hands and a radium-coated seconds hand tip, a rotating bezel, and a Seahorse medallion caseback. French commercial diver Alain Julien, who wore his daily from 1958 to 1959, praised its extraordinary robustness and precision, saying no rival watch matched its underwater durability, that it showed no defects despite brutal shocks, cold water, and great depths, and that each diver completed over 1,500 dives; the reference is 213.30.42.40.01.001.