Maybe I'll check around the area first, I've had it apart to clean it, it's the 120 medium model, I've seen listings on eBay for the 35mm model which was much more popular I guess. I did notice that the negative wasn't extremely flat though and now I wonder if I shouldn't just use the regular negative carrier, I have 645, 2 1/4, 6x7, etc.. I'll look at these too. I have and use the Negaflat for 4X5 so flatness isn't an issue, it's a beautiful design although it scratches the edges so contact print thereafter aren't very nice.
For 5x7 I have a "Zipper" glass less carrier, a design that preceded the Zone IV out straight by decades. The negative is stretched out so it is as tight as possible. I wish I had one for 2 1/4. They made them but getting one now is like winning the lottery.