I wanted a very compact way to connect a "proper' cable to a stepper motor that had the usual 4 x floppy wires.
The design is optimised for wire of 8mm cross section, but the slot in the cable outlet is intended to take a cable tie and can grip down to 6mm (or smaller with a modification, or a bit of filing)
It is intended to attach with epoxy glue. Mainly for compactness, and there should never be any need to remove it.
There is just enough space in the box area to contain a set of spliced wires + heatshrink. Cut the wires as short as you can to still be able to solder the connections.
You will need support. Print with the large flat face down.