It's one of the various patterns of drill tunic that were worn.
This is only one of a few images of an SS hat that I know of where it can be positively identified as being of the Imperial or earlier style.
Note the leather peak and second pattern eagle.
Just as reference.
Is that Ludendorff in the photo I posted?
No, in this photo FB
He and I share the same birthday, in fact. How droll.