This is a fidget Spinner that uses M12 nuts as weights. These should be glued in place.
There ten versions:
-- for a 6000 bearing (10x26x8mm)
-- for a standard 608 skate bearing (8x22x7mm) + compact version (smaller diameter)
-- for a 6900 bearing (10x22x6) + compact version (smaller diameter)
-- all as tri or double spinners
The 6900 bearing has the same height of 6mm as ISO 4035 or ISO 8675 M12 nuts.
The provided bearing caps are meant to be pressed into the center hole of the bearing. If the caps do not fit you can adjust the paramters to your liking here: http://www.thingiverse.com/thing:2083000
EDIT: Added double spinner versions for all three bearing types and sizes