Microscope Slide Tray, Polystyrene, Pack Of 6 Microscope slide storage tray designed for 20 each 3" x 1" slides. A unique stepped cutout design simplifies removal of slides and is designed to avoid direct contact of prepared slides with the tray surface. Polystyrene trays nest within each other. White color provides good contrast for viewing dyes and stains. Measures 11.25" W x 7.5" D x .75" H.