This is an adjusted part from the MMU3 Buffer Simple Loading Helper by Ruedli
I have had better luck after making some slight adjustments to the fit. Time and use will tell if it offers any improvements.
The author remixed this model.
This is a rebuilt filament guide version to better fit the newer R4 "B" version of the Prusa buffer cartridge. The R3 “A” version and the R4 “B” version have some slightly different dimensions which just don't quite fit the same.
This only alters the filament guide and the original handle nut/screw and clamp still work.