Ah!...........sweet memories, had to go to the aircrew shop in Düsseldorf to get mine, I was based in Germany at the time, Verden to be precise.
Made Avigation correspondence course and the exams a lot easier just by having that cursor on the front. Still got mine some forty six years later!
(6080 will do for me, the difference is less than the thickness of a Navigators pencil!).