I made this top mount spool holder for my Kobra 2 Neo in order to minimize the amount of space it takes up. The roller moves very smoothly with 2x 608 bearings (skateboard bearings). This does require supports and the roller should be printed vertically. When assembling, ensure the bearings are seated all the way into the slots they fit in to (pushed all the way to the ends. This allows space between the bearing and the roller and makes sure it rolls smoothly. This requires 2x M4x12 screws for mounting to the top. This will mount on any printer that has top mount holes spaced 31mm apart. You can also use T Slot Nuts to mount it on any printer that has T Slot Extrusion Rails on top. It is pretty much universal in that case. The bowden tube can then be trimmed shorter as seen in my photo. Enjoy!