Filament Guide Tube Guide
thingiverse
The Prusa features a filament guide tube (e.g., bowden cable) for smooth operation. Purchase a 2ft length from McMaster-Carr at http://www.mcmaster.com/#8547K23. To install, slide the tube onto the protruding threaded rods on the top, insert your filament, and enjoy its secure fit without needing to mount it onto the extruder.
Download Model from thingiverse
With this file you will be able to print Filament Guide Tube Guide with your 3D printer. Click on the button and save the file on your computer to work, edit or customize your design. You can also find more 3D designs for printers on Filament Guide Tube Guide.