he 196-1 allows complete flexibility, combining the features of the previously offered 191 and 192 eyepiece units. A rotating filter disc provides five options: "see-through" capability, reticle projection, green-filtered light, beam splitter with no coating, beam splitter with partial coating. A built-in diffuser may be engaged for even light distribution over the entire field of view when autocollimating, collimating, or colineating. By removing the light source, the 196-1 operates as a fixed right angle eyepiece. The unit comes complete with model 509 light source.