Could anyone identify these masks

hi there. would be great if anyone could identify these items which had been included with a Leitz Focomat IIc enlarger.

thank you! : )

7 x 7 cm with openings of 5,4 x 5,4 cm & 3,9 x 3,9 cm

Several different sizes as 45 x 60 / 37 x 52 / 32 x 40, thin metal with black matt coating & egistration marks

Masks for (which) enlarging easel?

They look like film holders to fit in the enlarger, not masks for an 'easel' that sits on the baseboard.

54mm x 54mm is the so-called '6x6cm' common 120 film medium format size, while 39mm x 39mm was a common 127 film format size.

The '645' medium format size is actually 56mm x 42mm and is awkward to fit in an enlarger that has the film running across its throat. I suspect that mask may be to allow the film to feed front-to-back into the enlarger and make better use of the baseboard dimensions.

Never heard of any formats measuring 37mm x 52mm or 32x40. Although the latter could be a rectangular 127 film size.

Having said that: People collect all sorts of junk that they think might come in handy. My own darkroom is littered with such bits and pieces that have absolutely nothing to do with the enlargers I own.