A nice example for this WWII anti-aircraft artillery unit, part of the La. NG.
The 204th Coast Artillery (AA) was organized using elements of the156th Infantry, part of the Louisiana National Guard. Inducted into federal service January 1941; later transferred to San Diego, Cal. to provide anti-aircraft defenses just after the attack on Pearl Harbor. Inactivated at San Diego in September 1943 and redesignated HQ and HQ Battalion 204th AAA Group.
This DUI was has no maker markings. Screw back.