Kriegsmarine Zeiss optic light battery box 'blc'

A very rarely seen original Kriegsmarine issue battery box as would have been used with a variety of KM issue optical instruments. 
 
This particular example has received a dark green reissue finish to the exterior, whilst remains of the shipboard grey colour remain visible to the interior, as shown. 
 
This example is also very nicely 'blc' maker code to denote manufacture by Carl Zeiss Jena - perhaps the most ubiquitous maker of KM optics, yet far more rarely seen in terms of optical accessories such as this. 
 
All internal fittings and electrical connectors remain in excellent condition!