I found it... On page 142 of "Uniforms and Traditions of the Luftwaffe, Volume 2" by Angolia and Schlicht, Personnel of the Chief of Supply and Procurement (Generalluftzeugmeister- GL) was comprised of Civil Technicians that were assigned as controllers of armament factories in the Reich and occupied territories. Very little is known about this organization, but most period photos show these men wearing fliegerbluses. They would wear, either on collar tabs or punched through the collar, the letters "G" and "L". Often the "G" would be on the wearer's right collar and the "L" would be on the wearer's left collar. Although, there are photos that shows both letters being worn on both collars. Their national emblem consisted of a cogwheel with the luftwaffe eagle superimposed. This breast insignia was a pin back, like the metal eagle worn on the standard LW summer white uniform. If you want to "see" what I am talking about, please shoot me a PM. What are the heights of the cyphers?