Filament Ballast

Since I started using my low friction Universal Spool Holder published here http://www.thingiverse.com/thing:1614533 once in a while, when extruder rapidly pulls the filament, several convolutions of the filament become loose. They then overlap each other and eventually may block the filament flow. This causes print to fail.
The solution ended-up being very simple. I used old 608 bearing as a ballast which hangs on the filament. Initially I simply hung it on a paper clip, but then decided to d