Ihagee AG Dresden A16 Mikrozwischenstück Extension Tube Set Microscope Adapter. Any wear and tear is visible in pictures. The clasp holding the black piece latch closed appears to be minorly bent but appears to function well all the same. The lid to the box is also missing.
A great piece of photographic history in overall great condition for anything from the mid 1940s. Look over the pictures and see if this is what you are looking for.
This item is in the category "Cameras & Photo\Lenses & Filters\Lens Adapters, Mounts & Tubes". The seller is "johnus_yhrnsgrd" and is located in this country: US. This item can be shipped to United States.