Prusa i3 Mk2 Filament Holder Tube

I wasn't too happy about the original holder that comes with the Prusa i3 Mk2, since you have to move the holders to accommodate different width spools of filament. So I designed a tube that fits between the holders. The tube is 90mm long, so it fits Prusa spools or narrower.

v2 is designed with an oversized internal diameter (0.5 mm clearance), which gives a nice fit on the Prusa holder arms, as well as chamfered edges for easier insertion. It also has a 3 mm smaller outer diameter to keep