If anyone is interested, I'd like to trade my clean, working Calumet C2 roll film holder for a clean, working 4x5 Grafmatic film holder with six septum in very good condition. I'm seeking the later model Grafmatic, which locks after the sixth sheet is shot and slides under a standard hinged back (i.e. not the wider model that only works with a Graflex back).

If you can help, please PM me. Here's a short description of the C2, if you're not familiar with it:

The Calumet C2 120/220 roll film back may be used with any 4x5 view or field camera with a spring-loaded or Graflok back. It slides into the camera back like a sheet film holder, without having to remove the ground glass frame. The C2 offers an economical alternative to 4x5 sheet film, along with the perspective controls benefits of a large format camera in medium format (6x7). It accepts both 120 (10 exposures ) and 220 (20 exposures ) film rolls.

Thanks for looking,