Rolleimarin IV Underwater Housing for use with a Rolleiflex 3.5f Camera (not included).
I don't think this housing was used - has some storage marks that you can see in photo.
Comes with a complete set of gaskets (these are custom-made laser-cut, high-quality) and the original green canvas carry bag (has name of previous owner).
Also includes the camera mounting pieces for focusing, aperture, speed, and filters.
Yes - because it has to work with controls and the viewfinder has to be removable. Earlier Rolleimarins worked with different models -it's all on the Internet