Arm of service was indicated by the colors or waffenfarben, which appeared on the head-dress, collar patches, shoulder straps and collar piping.  In this case, yellow denotes flying troops, parachute troops and supply.

     The top image is the collar patch. It was worn on the collars of the tunic.  The middle image is the shoulder strap and it was worn on both shoulders collars of the tunic.

     The bottom image is the shoulder patch which was worn on the left shoulder only.