The carrier was made by a New York company, it's built like the Durst enlarger, sturdy, heavy, precision, or other words a piece of mechanical art. It has two sheets of antinewton gladd and the carrier is different in that it has precision stainless steel rollers on the sides. It was made to accommodate 5" wide roll film. It is new.
All that said it's like everything on this "project", it fits but needs some special help. I still don't have a head for the enlarger. It's looking like I'll be inventing a light trap. Maybe one that drops down. I can't see how the slip in carriers work. My Beseler has a lever that sandwiches the carrier and my Omega the same.
Maybe I need to make a wrap around piece that makes the carrier like a filter drawer cover. That's the design issue.