This allows you to mount a SD card reader or extension at the back of a Quadra 700 via a NuBus slot cover, so you don't have to open up the case to access your SD card (if you're using BlueSCSI, SCSI2SD, ZuluSCSI, etc). I used a 48cm SD card extension cable (just search eBay for "sd card extension cable" to find one like mine; they all seem to be the same generic item).
You have to use a thin tool (pliers, etc) to push the SD card into the reader, since it'll be so recessed into the bracket.
It might also work on other Macs as long as the slots are the same as a Q700, but I haven't tested any.
I recommend PETG rather than PLA, since PLA is brittle and the tab will break off easily.
I used a bit of hot glue when attaching the SD card reader to the bracket. This ensures it stays in place when you push the SD card in.
The author marked this model as their own original creation.