TISSOT. A GENTS STAINLESS STEEL AUTOMATIC CHRONOGRAPH WRISTWATCH.   Model: Navigator. Case reference: 45 501.  Date: Circa 1970's.  Movement: Signed Tissot 2170.  Dial: Signed, silver and black, luminous batons, black minute and hours hands, orange seconds and minute hands for chronograph, black subsidiary dial at 6 o'clock position for chronograph hours, black sub dial at 9 o'clock position for seconds, date aperture at 6 o'clock position, inside black tachymeter with white numerals.  Case: Signed, stainless steel.  Strap: Later replacement brown leather strap, steel pin buckle.  Size: 39 mm.  Accompaniments: Tissot semi rigid travel case.