I haven't seen one of these exact devices before, but extrapolating from my own Meopta this would replace the standard negative carrier completely - that can be seen by the rails for the pressure springs on top and by the focussing device at the back of the carrier.
I think it is probably a sheet film holder for 6,5x9cm sheets. Does the rectangular plate with the brass screws lift up? Somehow the anti-Newtons-rings glass would go on top of the film to keep it flat, so lifting the plate (via the brass handle??) might enable this in some way. Or is the glass we can see a double glass where the sheet could fit between two glasses?
Note: I have a mounted slide carrier and it is a single piece with a couple of spring clips, which fits where the lower glass or plate would sit - so nothing like this device. You could try sending the pictures and the part-number to Meopta and Fotoimpex (who stock many spares for the enlargers) to see if they can help.
Last edited by MartinP; 01-03-2014 at 04:38 PM. Click to view previous post history.