Opus Chronoswiss, Chronograph No. 4853, Ref. Cal 741S. Excellent example, skeletonized, self-winding, water-resistant, 18 karat yellow gold gentleman's wristwatch with gilt-finished lever movement visible between two sapphire crystals, circular water-resistant-type case with coin-edged bezels, Arabic and baton numerals, four subsidiary dials indicating constant seconds, date, with 18K gold Chronoswiss clasp.