Russian Stereo Attachment for Contax

[didi]

I would like to know what is the hole on the top, is there any accessory that is missing.

 

[solienear]

Hello,
this very rare russian stereo attachment is the only copie from Zeiss, but without close up for KIEV camera.A other stereo attachment from ashai pentax is for SLR cameras with 49mm screw. The russian stereo attachment have 40,5 screw for Contax/KIEV rangefinder lenses.
You need or not need that's the question your answere himself.