Special Features:

Includes pin, spring, p/n ms171436, nsn 5315-00-844-5644 and ring, objective focus stop, p/n 188d0022; ring protrudes 0.250 inches from one face of ring; spring-press in place

Properties:

A cylindrical item having an internally flanged diameter designed to retain a lens or window in the objective end, or a diopter scale at the viewing end of an optical instrument. It may have one or more of the following characteristics: internal thread or machined for a press fit, method of securing, and/or knurled periphery. For externally threaded items, see retainer, optical element. Excludes cell, optical element; nut, plain knurled; nut, plain round; and ring, retaining.