The #6000 is the is the large bearing on most 21 size engine like the K21, MAC 21, A/A 21 and the CMB 21.
Dimension: 10mm X 26mm X 8mm(.3937” X 1.0236” X .3149”) ...
The #6001 is the large bearing on most 45 size engines like the K45, A/A 45, MAC 45 and the CMB 45.
Dimension: 12mm X 28mm X8mm (.4724” X 1.1023” X .3149”) ...
The #607 is the small bearing on most 21 size engines like the K21, CMB21, A/A21 and the MAC 21.
Dimension: 7mm X 19mm X 6mm(.2755” X .7480” x .2360”) ...
