Ring and Bead SIght

I am in the process of cleaning this relic gunsight up.

Does anyone know which gun it may have been used on?

It is made from brass. The square rods are 4mm x 4mm – so I assume it is German.

The brass bars would have intersected in the middle. There are no markings on it.

I assue, it was used in an offset sight or multi barrel gun ?

The std MG15 gunsight is down the barrel and not offset like this[ATTACH=CONFIG]218915[/ATTACH].

Thanks for any guidance.