Omega D5500 carriers look like this. They are not interchangeable with the D5 unless the D5 is retrofitted with the special cassette. If you got some of these, probably best to resell on ebay.
I'm trying to clear up a couple details on D5500 negative holders/carriers. In the Omega parts/accessories list, there are 4 negative carrier holders listed, C-size (423-950), D-size (423-951), Film Strip (423-952), and Rapid Shift (423-953). The C- and D-size carrier holders I understand: simply insert mask sets into them for various formats (within the C or D size ranges), then insert carrier holder/mask set assembly into the negative carrier casette; I have a few of these two carrier holders and mask sets.
Film Strip Carrier Holder and Film Strip Masks:
I believe I understand what the film strip carrier holder is as well; there are a few sizes of film strip masks that can be inserted into this carrier holder. I'm 99% sure I have one of these without any masks, however I have found it nearly impossible to find a photo of one of these carrier holders anywhere online other than the first image below (from a sale listing here on Photrio from a few years ago). The next few photos are of the carrier holder I have (including in a disassembled state to show the internals). It seems like I might be missing the piece circled in red, what is it's function and how important is it? (the fifth photo below shows the mounting screw holes and indentation where I believe it is supposed to sit).
Rapid Shift Negative Carrier Holder:
What is this? I can't seem to find a photo of a D5500 version anywhere. I do have another style of carrier holder, but I believe it's the Universal 5"x5" Glass Carrier (423-920, shown in the last photo in comparison to a C-size carrier holder with 35mm mask set).
So presumably the Rapid Shift holder is something else? Is it just one of the holders where the edges curve down to accommodate a full roll of film?