Omega Constellation 1551/861

An Omega Constellation chronometer bi-metal automatic wristwatch, having a round cream baton dial with date at three and yellow Roman bezel, fitted to an integral barlink bracelet with signed clasp, model ref. 1551.861, case ref. 60119124, movement calibre 1120, inside case engraved Omega Watch Co 368.1201, case dia.35mm, overall length 200mm, bracelet w.21 to 18mm, gross weight 102.3g