Thanks Don! From what i found it?s supposed to be: "The STH was the logo of "Der Stahl Hof", the Stahlhelm's own little PX for members. They sold everything from plaques of Franz Seldt to trinkets for the sweetheart." and: "Like all Stahlhelm activities, the STH was centered in the founding district of Magdeburg. Don't know the true maker of the badges, and we'd probably need the contract records to find out." That particular "makermark" comes from a Stahlhelm badge.