US Army First Sergeant rank insignia, in use 1920-1942
Derived from w:Image:US Army E-8 1SG.svg and w:Image:US Army E-7.svg with colour changes per w:Image:WWII2NDSGT.gif. Authoritative reference: http://www.tioh.hqda.pentagon.mil/Rank_page/History_of_Enlisted_Ranks.htm