This is a clip on spool holder that uses the stock spool bar from the CR10. the extra material around the arms really does help beef up the strength. I might make it a little thicker if there is a demand for it.
First clip it in place, it works in either orientation. Then place your filament on the spool holder and tighten the nuts on the end to secure it in place. I've noticed minimal movement while printing.
This was part of my build to remove the control box from the printer.
EDIT: Since people asked for a part that had the clips on both sides I have added a model for that.