Gentlemen,

although I am not sure for 100%, the DRGM mentioned on the receiver could be DRGM No 1379234:



As the Abbreviation DRGM appears on the receiver together with the word Sicherung (safety), DRGM #1379234 could match.

Said DRGM was filed by Meffert on 12. May 1936; it was registered on 8. July 1936.

Regards

Martin