Masking box mystery

Hi all, thanks in advance for any information you might be able to tell me about this. At its widest it can open to about 7" X 6.5". There are no markings on it, so I have no idea what company might have made it but I'm relatively sure it's darkroom equipment.

Thanks again!

Attachment 199411Attachment 199410Attachment 199412

its a negative carrier with a cropping device. ( dry plate ? )
like the olde tyme version of the Durst SIVONEG but for big negatives
https://www.google.com/search?q=Durs...=1918&bih=1169

Thanks so much, you've given me some good information so that I can continue the research.

S