Proper orientation of the filter is necessary in order to minimize autofluorescence and maximize performance. There is a caret (arrow) located on the edge of each filter in order to aid orientation.

Excitation (x) filters should be positioned with the arrow pointing toward the specimen, toward the inside of the cube, and away from the light source.

Emission (m) filters should be placed with the arrow pointing toward the specimen, toward the inside of the cube, and away from the detector/eye.

Transmitting mirrors/polychroics, such as Yokogawa and others, are mounted opposite those for all other equipment. These mirrors should be mounted with the coated surface toward the sample and detector. The Trans PC have an arrow pointing toward the coated side.