This is a case for the Ultimate II+ tape adapter. The design is based on the look of another tape adapter on thingiverse by VIC_Camelot: https://www.thingiverse.com/thing:2412824
It's designed from scratch in Fusion 360, and might not be as nice looking as VIC_Camelot's design. However, the dimensions of the tape adapter I had, didn't fit with his design, so I designed my own.
This design includes holes for M3 square nuts and M3 bolts. At the time of writing this description, I've forgotten the bolt length (maybe 10mm?)