I have found my Grandfathers old Heuer Stopwatch that he used for timing his greyhounds and I need some help to identify it. The stopwatch face has green segments for timing field sports (waterpolo, ice hockey, basketball, handball, hockey, rugby & football). The back has a red sticker with the Heuer logo, 2 white boxes (top REF), words "unbreakable mainspring shock resistant anti magnetic level 7 jewels". If anybody can help me with identifying this I would be greatful