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 96529 Tune-Up Kit for .7 hp Motor, Front and Rear Exhaust
Dynabrade 96024 Tune-Up Kit for Orbital Sanders
Dynabrade 79850 - 5" Universal Vacuum Hole Interface Pad
Dynabrade 78007 1/2" W x 12" L Medium Non-Woven DynaBrite Belts, 10/pack
Dynabrade 90400 1/2" W x 24" L Very Fine NWN DynaBrite Premium Belts, 10/pack
3M 00949, Scotch-Brite Clean and Strip Disc, CS-DC, SiC Extra Coarse, 6 in x 5/8 in, 7100054081 