The Omega Speedmaster Automatic Day/Date Ref 3520.50.00 is a triple-date chronograph. Its classic Speedmaster case design features twisted lugs, a tachymeter bezel, and large pump-style chronograph pushers. The dial features set this model apart from the traditional moon watch, with a triple calendar, a day and night indicator, and sub-dial registers at the 6, 9, and 12 o’clock positions.