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″.
setting ring when supplied may be .20008″.

Dynabrade X51 5" (127 mm) Dia. Non-Vacuum Dynorbital Extreme Random Orbital Sander, .3 HP, 12,000 RPM, 3/16" Orbit, PSA
Insize 4120-10, METRIC THREAD RING GAGE, GO, M10x1.5, 6928640341458
Dynabrade 11518 Rubber Drive Wheel
Dynabrade 01494 Air Inlet Bushing 