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″.

3M Cubitron 3 Fibre Disc 1182C, 60+, 7 in x 7/8 in, Die 700BB, 100 ea/Case, 7100349579 