R.F.C. Staff Officer’s armband or brassard, 1917.  This is the third version; the first version introduced in 1915 did not carry the initials "R.F.C." The second version introduced in February, 1916, added the initials and the background was a light blue/green color.  The third version replaced this background color with a white material.  These armbands can be seen in the four contemporary photos below, beginning with a cropped photo of A & C flights of No. 57 Squadron showing an observer wearing the armband; the next photo shows the Chaplain of No. 40 Squadron, Padre Keymer, followed by an Area Intelligence Officer wearing the armband and lastly a photo of Trenchard - with Maurice Baring to the right - with other others including one on the left wearing the armband.  Notice how the armbands always are worn on the right arm.   The very last image is of the 2nd version.