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 19076, E-A-R Classic Probed Test Plugs 393-2003-50, 50 EA/Case, 7000052882
3M 26046, PPS Series 2.0 Adapter, Type S15, 3/8 Male, 19 Thread BSP, 7100135334 