D-shaped center back ring for attaching the main shoulder straps of a German backpack. It was used with mountain (Jäger) backpacks, Luftwaffe backpacks, infantry backpacks of the end of the war, etc. The material is aluminum, the surface is sandblasted. It is made at the factory equipment in Germany, in the same place where such accessories were made during the Third Reich.
Internal dimensions 47×38 mm, where 47 mm is the width of the straight part of the ring (the width of the strap). External dimensions are 65×50 mm, respectively. The wire thickness is 6 mm.
The price is for 1 ring.
2 similar rings on a early mountain backpack (with alu parts). Original rings were more "roundy" and more "flat", used without any system. Source of the photo: wehrmacht-awards.com/forums/