Tudor Oysterdate Chronograph Big Block 79180The third series in blackThe third series of chronographs from Tudor has a third sub dial and were the first automatic chronograph from the Wilsdorf stable a full decade ahead of the reference 16520 Rolex Daytona. Due to the addition of the self winding rotor on the movement, the case was extra thick, hence the Big Block nickname. This example houses a black dial in perfect, original condition. The case remains in good strong condition and the bezel