This is a small SSD mounting adapter for my Synology DS218+. Theoretically this should also work for other "slot"-type drive cages.
Note that the latch is missing the little pin on the front.
Original source for the adapter plate: https://www.tinkercad.com/things/jHUGbb1cVdR
Original source for the latch: https://www.thingiverse.com/thing:4852787