A rare (I think) twin mount of 2cm MG151 guns. I had seen single and triple mounts but never a twin mount..... Standard mount or local makeshift ??

Image from Ebay
Sturm78
Looks a little bit like a Schwebekreisvisier - two rings at an angle can be seen inside the circular sight frame, although the Schwebekreisvisier had only one ring; there was also a later variant of a simple iron Flak sight, I cannot remember its name at the moment - maybe it is this one. Linealvisier used a kind of a ruler with a handle, which could be rotated in the plane of the frame (accordingly to the direction in which the target was flying).
Yes, it is the 2 cm Flak 38, I wonder if it's not a naval shield?Well, here an image from Ebay. I think a 2cm Flak 38 gun with a non-standard shield. It seems mounted on a vehicle