I designed this colar for sunlu 1kg filament reel on my ender 3. But it may fit others too.
The hole diamenter on the reel was 73mm. This will reduce it to 37mm.
The reel wasnt dispencing efficiently due to the large hole in the reel and only a small diameter holder for it to run on.
this should help it run a little more smoothly and stop most of the swing and jolting it did before.
build them yourself let me know how you get on.
Update to the clips to make them stronger.