A graduated scale, usually cylindrical in shape, attached to, or forming a part of, the focusing nut or knob of the eyepiece of an optical instrument. It is read in conjunction with a line or dart indicator to measure the change in refracting power of the eyepiece, in diopters, and introduces correction to compensate for the eyesight variation of the observer. It may have a knurled periphery and/or teeth on the inside diameter.
Classification: Military equipments not identified by kind
NSN 6320-00-845-3261
NSN 5996-01-254-9963
NSN 5855-01-474-6820
NSN 4140-01-435-7166
NSN 5990-00-838-1082
NSN 6645-01-575-2297
NSN 2925-01-643-2112
NSN 5965-01-221-0569
NSN 5990-01-277-2118
NSN 7035-00-406-0568
NSN 5930-00-528-1918
NSN 5915-01-229-1726