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 ISY-200-3, BASE PLATE, 6940561974720
3M 26103, PPS Series 2.0 Adapter, Type S19, 3/8 Female, 19 Thread BSP, 7100135928 