Cylindrical Plain Ring Gauges are used to check external diameters of straight round parts and to set other gauges, such as bore gauges, internal micrometers and air gauges.
Cylindrical Plain Ring Gauges are precision lapped for best accuracy and finish, are available in inch or metric sizes.
Common Ring Gauge tolerances:-
British Standard Tolerances, BS 4064 ( Metric sizes ) & BS 4065 ( Inch sizes ) Grade A, Grade AA, Grade B.
American Standard Tolerances, ANSI/ASME B89.1.6-2002 Class XX -Dependant on the size, most common Class X, Class Y, Class Z & Class ZZ.