Stahlrute

[Deges]

Hi,

I've got this stahlrute in my collection. Did some research on it. But can't seem to figure out what the letters under Sipo mean. Does it say D. R. R. A? Because most of them are signed above and under Sipo. And usually with D. R. G. M. Anybody any ideas on this one? All the info is welcome.

Thank you very much!