German WWII Navy 20mm or 40mm Bofors/Oerlikon anti-aircraft cannon, day or night, optical gun sight.  Marked:DZC/2, with 4 power by 15 degree field of view.  Code:  bmk.  Nazi eagle over swastika with M (Marinen) on left side, and IV (Nazi Naval Department for Optics) on right side. Optics housing is 4" in diameter and 3" wide, all painted naval grey.  Dovetail mounting base.  Flip up rubber eye cup.  Choice of dark or light polarizing filter adjustment built in.  Optics are magnesium flouride coated.  Top of sight housing has built in open gun sights with radium outlines for night use.  Unit weighs 6 pounds. Unissued.  New condition.  $450