A Greener 608ZZ Bearing Based Spool Holder

I've been using my glass marble based turntable (https://www.thingiverse.com/thing:10018) to feed filaments for a while. It works well except when a filament spool is close to be depleted, the spool becomes too light and could be pulled away from the turning center. Then it cease to turn. Things get even worse with 2mm filaments, since they are even lighter and the spool diameter is smaller. So I designed my 608 bearing based spool holder. I'm quite happy with the result.
Features:
1. No lar