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″.

Insize 3127-E3, DIGITAL THREE POINTS INTERNAL MICROMETER, 2.5-3"/63-76mm, 6928640356377
3M 26102, PPS Series 2.0 Adapter, Type S16, 3/8 Female, 19 Thread BSP, 7100135934 