For zero setting of inside micrometers, three points internal micrometers and bore gages.
Deviation is the difference between the ordered size and the size marked on the setting ring when supplied.
For example, the ordered size is .2”, the size marked on the setting ring when supplied may be .20008″.

Dynabrade 55409 Valve Body Housing, Pencil Grinder
3M 80760, Flap Wheel 747D, T83, 2-1/2 in x 1 in x 1/4 in, 80 X-weight, 7000045315, 10 per case 