Seabees assigned to Naval Mobile Construction Battalion 133 set up communications equipment for their two-person fighting position during the Battalion's annual "Black Hell" squad competition. The Seabees use their combat warfare skills to complete each portion of the competition. The competition is held in honor of the Seabees of the 133rd Naval Construction Battalion who fought on Iwo Jima during WWII. The 133rd NCB lost three officers and 39 enlisted, with 12 officers and 191 enlisted wounded in action; the most casualties in Seabee history.