Help with a Beseler mask device

[Photographica]

I apologize for not describing this device correctly but I don't really know what to call it.

I got the "contraption" in a box of misc darkroom items at an auction. It appears to be useful as a universal negative mask. There are adjustments on two sides that move shutters across the 5 inch square opening -- essentially permitting one to create an opening anywhere, of any size within the square. (see pictures)
I plan on adapting this to my 4x5 chromega enlarger.
The only markings on it are "Charels Beseler Company Cat. No. P 106"
I've not been able to find information through the typical search environment. The Cat. number doesn't seem to follow current Beseler numbering systems.

My questions to anyone who has seen, or might even have, one of these are:

• Is it complete?
• Which Beseler enlarger is it designed for?
• Or for that matter: What is it called?

Thanks for any insight you can provide....
Bill

 

[George Nova Scotia]

Looks complete, likely for the 45MX series assuming the opening is 4x5.

Omega made one as well. I have one NIB labeled Mask Set. Picture below. I think the main difference will be in the centering/locating studs on the bottom. The omega negative stage has a slightly smaller opening, the four silver studs are used on the omega. Looks like there are four similar items on the Beseler just rotated.

 

[Roland126]

Old post I know but......
Photographica,
Did you ever figure this rig out? I have acquired one along with a Beseler 45MCRX. It really doesn't seem to fit amywhere!