Per Uniforms and Traditions of the Luftwaffe, Vol 1, page 579-580: There were two divisions of the Home Defense AntiAircraft Artillery 1. Home Flak Batteries 2. Alarm Flak Batteries These men seem to be members of the "Home Flak Batteries". This organization consisted of civilian personnel. Men eligible were born between the years of 1883 and 1925. Many members were either unfit for military duties or worked in critical civilian jobs. These men were issued the LW fliegerbluse, collar liner, long trousers, greatcoat,lace up boots, a one piece protective suit, and an ID tag. The fliegerbluse and greatcoat were both void of any insignia and shoulder straps. These uniforms had to be from used stocks. The "Deutche Wehrmacht" or "Deutche Luftwaffe" was to be worn on the upper left sleeve. Just for reference, the Alarm Flak Batteries were manned completely by Heer, Kriegsmarine, Luftwaffe, or SS crews assigned to Homefront billets. All members and officials up to and including the rank of Major were obligated to duty. These men wore their uniforms(even officials) with a protective suit and helmet. It was common to have AAA Crews that consisted solely of officers and officials! The photos look like they are in some sort of training environment.