The variety of shoulder flashes that existed during the war years was extensive. Wartime mobilization saw the corps grow to unprecedented levels. The need for insignia grew as a result.
The schedule of adopting shoulder flashes differed from division to division. The move from distinguishing patches with RCASC on them to shoulder flashes over plain divisional patches depended on theatre of operations.
The early shoulder flashes included a white border on them. Effective Jan 21st 1944, this white border was ordered removed. Flashes worn by units overseas were spelled out in full, while the smaller RCASC titles tended to be worn in Canada. Second World War titles differ from post war titles by having "Royal Canadian" over "Army Service Corps" . Postwar titles have the word "Army" on the top line.
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Both of the above titles were made by the same UK manufacturer. Variations and limitations of supplies during the war sometimes resulted a variety of colours. The one the left is done on an almost black material while the one the right is close to purple.
The use of the abbreviated RCASC titles tends to have been for troops stationned in Canada. Troops assigned to active units overseas wore the fully spelled out Royal Canadian Army Service Corps titles.