Rolex: A steel Oyster chronograph anti-magnetic wristwatch, the black dial with outer telemetric and tachymetric scales, Arabic numerals, subsidiary dials for running seconds and elapsed minutes, sweep centre seconds operated by two round buttons in the band, the case with screw-down winder and screwed back No. 185930 3525, with makers mark, the signed movement jewelled to the centre with 17 jewels