190801-N-BN978-033 GREAT LAKES, Ill. (Aug. 1, 2019) Chief Operations Specialist Richard Jackson gives a tour of the OS "A" school's Ship's Self Defense System lab to Republic of Korea Fleet Master Chief Yong Hee Kwon during a visit to Center for Surface Combat Systems Unit Great Lakes, Aug. 1. (U.S. Navy photo by Brian Walsh/Released)