Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:3012953.

I did not like the filament holder for the Alfawise U20 and wanted something to mount on top of the printer due to space. I looked at existing Cr-10 options since they have identical frames but did not see the exact solution so I modeled my own. It uses short m5 screws and m5 tnuts. I printes at 50% infill but am sure you can go with a bit less.