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 43493 Cover, Rear Exhaust
Dynabrade 92180 1/2" W x 30" L 40 Grit A/Z DynaCut Belt, 50/pack
Dynabrade 69451 Drop-In Motor
3M 00949, Scotch-Brite Clean and Strip Disc, CS-DC, SiC Extra Coarse, 6 in x 5/8 in, 7100054081 