Designed for dry darkfield microscopy techniques, the BRESSER 0.85 NA Darkfield Microscope Condenser helps to improve the contrast of transparent unstained specimens like tissue samples or single-celled organisms by eliminating unused light to produce a dark—almost black—background with a bright image in the middle. Because so much light is eliminated, you must make sure the sample is strongly illuminated to see it properly. This condenser has a numerical aperture (NA) of 0.85.