Special Features:

Non-magnifying; 5 mm ruled scale w/0.1 mm divisions; 21 mm outside diameter; 1-2 mm thickness; 50 graduation lines; whipple; clear color

Properties:

An item, usually made of glass, having fine wires or hairs, or etched or printed fine lines on a surface, and placed in the focal plane of an optical instrument to establish a reference point to the axis for the purpose of aiming, measuring, ranging, and the like. Excludes lens, optical instrument.