Each dish has a flat (0.17 mm thick) optical quality glass bottom, allowing the use of a short objective working distance, large numerical aperture (NA), and a high magnification (up to 100x). The larger NA and higher magnification provide superior quality imaging for both classical and fluorescence microscopy. Higher effective NA yields brighter images for fluorescence and higher resolution in Image Analysis. The glass bottom permits the use of immersion objectives with medium such as water, glycerine or oil for the highest magnification possible. To optimize heat-exchange, glass-bottom dish is designed to be flush (flat) with the microscope stage or heating unit, therefore eliminating the air gap that exists with modified plastic dishes in which a glass cover slip has been inserted.