In 1976, Tudor launched the third family of chronographs, known as the "Big Block" by collectors, along with a significant innovation. The brand introduced its first Chronograph with automatic movement thus building on the foundation laid by the Oysterdate family of watches.
The 79100 series consisted of three distinct references; 79160, 79170, and 79180, each distinguished by a different bezel insert. The 79160 features a black aluminum tachymeter bezel, the 79170 has a black aluminum 12-hour bezel, while the 79180 is fitted with a stainless steel tachymeter bezel.
One of the most notable features of the Tudor 79170 is its reliable and precise Valjoux 7750 automatic movement. This movement powers the watch's chronograph function, which allows for precise timing of events up to 12 hours. The watch also has a date function located at the 3 o'clock position on the dial.