This is for use on the Prusa i3 MK3s ,Mk2.5s, MMU2s without the filament sensor on the hotend. If your having issues with the new MKs print head jamming your filament or producing a restricted filament path this should help. It takes just a few minutes to add and is made to work with M10 Pneumatic push fittings. Can be found here.
This will create a pass-through for your PTFE tube to go inside the FS cover up against the adapter. The pathway has been changed in this version to promote self guided filament path and to help shape the tip as it is pulled back up in to the tube.
You will need the current revision of the Prusa MK3s and MK2.5s hotend as can be found here. https://www.prusa3d.com/prusa-i3-printable-parts/
I suggest printing the Big Bore parts at a higher resolution . Resolution of .15 will work but .1 is even better in this situation for a smooth channel.