US Army Technician 3rd Grade rank insignia, in use 1942-1955 (rank instated 1942, discontinued in 1955)
Derived from w:Image:US_Army_E-6.svg with colour changes and addition of "T" per w:Image:WWIIT3.gif. Authoritative reference: http://www.tioh.hqda.pentagon.mil/Rank_page/History_of_Enlisted_Ranks.htm