Iron Cross 1914 1st class, threaded version for nuts, reverse signed with a test "800", non-magnetic nuts.
Crosses of this type are often referred to as "Flyer's crosses", according to one theory, they were to be dedicated to aircraft pilots, due to the possibility of better attaching the badge to the aviation jacket.
operation: Carl Dillenius, Pforzheim
Diameter: 47.9 mm