This part sits on 2 LM8UU bearings that can slide along an axis aligned on the X axis.
It's designed for 3mm filament and has a notch to hold any filament guide tube with outer diameter inferior to 7mm. Drilling is possible to make that a little larger.
There are holes ready for zip-ties to hold the piece on the LM8UU bearings
Use double-sided clamps to create an elevated X-rail above the top of the printer.
This part was designed for Prusa Mendel i2. 3mm filament sometimes snaps when the extruder moves too far along the X-axis so this part's function is to maintain a little flexibility on the filament by maintaining the exit part of the guide-tube above the printer.
No post-processing required
No support material required