This thing doubles as a general purpose spool bushing which locks into the spool (snaps in place) and a means to spool loose filament using a drill. The bushing has an inset nut-lock so it can be tightened onto a threaded rod. It is intended to be use with the standard nuts and threaded rod with which a Prusa is built (SAE in my case). The bushing will fit a 1kg spool from Ultimachine or ProtoParadigm - and any other supplier who uses the same spool (as seen in the pictures).
More details and instructions are to come!