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 78290 2" Dia. x 2S Fine, Type R Unitized Locking-Type Disc, 25/pack
Insize 2307-1R, REVERSE READING DIAL INDICATOR, 1", lug back, 6928640396649
Dynabrade 64404 36" W x 60" L (914 mm W x 1,524 mm L) Metal Capture Downdraft Table, 230 V (AC), Side Exhaust
Dynabrade 51926 Vane Set (4pk)
Dynabrade 91573 6" Dynacut Extreme Orange Premium Film Disc, 100 Grit, Hook & Loop, Non-Vacuum, 50/Box 