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 5930-01-655-8883
NSN 5835-01-316-3255
NSN 5965-01-207-0991
NSN 5905-01-329-1083
NSN 5998-00-753-1581
NSN 5999-01-307-8454
NSN 6320-01-648-5538
NSN 5905-00-405-8361
NSN 6620-01-510-3501
NSN 4140-01-023-1537
NSN 7035-01-026-1171
NSN 5975-01-229-8786