They never made this for the D5500, so I made some masks out of the opaque plastic bag that paper comes in. It works very well because it does not 'shed' like paper or cardboard and it won't damage the glass like metal or plastic.
I set the masks on top of the glass carrier and hold it at the edge with a little piece of electrician's tape (that tape won't leave sticky residue).
You might want to try that if you can't locate the 4 blade mask.
Ok, I do have one. How about $25 plus shipping and something for APUG?
It's in fine shape.
If this works PM me with your zip code and address and we'll go from there. I'll look for the best shipping price for you and you can confirm it.
"We are what we repeatedly do. Excellence, then, is not an act but a habit"