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 56255 5" Dia. Vacuum Disc Pad, Hook-Face, Short Nap
Dynabrade 51669 Retaining Ring
Dynabrade 79481 4" Dia. x 2" x 3/4" Arbor Hole, Dyna-Felt Polishing Flap Roll 