Aluminium part with german numbers

[jarok34]

Hello, I found this part of Aluminum in South part of Poland and it is connected with The Battle of the Dukla Pass. I suppose it is a part of a radio equipment. Correct me if I'm wrong. On the Internet I found out the numbers and letters: 51976 dnz. 41 means that this is from the: Schwarzwaelder Apparate-Bauanstalt, August Schwer u. Soehne, Villingen. Length 32 cm, width 8 cm
Please help with ID.

[spaltring]

DNZ 41
41 is the year of manufacturing
DNZ is the company name schwarzwalder apparate-bauanstalt
Aug. Schwer Sohne,
Villingen/Schwarzwald

[jarok34]

Thanks, but already I know itp. Do you know what this part is? From what equipment?