Patek Philippe ref 3433, ca 1960, 18KYG, 35 MM case, with the legendary 27-460 movement. This automatic movement is chronicled by non other than Walt Odets in TZ?s Horologium, it can be found here: http://www.timezone.com/article.aspx?id=horologium&articleId=horologium631672832368975787
On a brown strap: