CapitolBrand M3453-2424 Glass Microscope Slide Cover Slip, 24mm Length, 24mm Width, #1 Thick (Box of 100) Cover slip to hold slide specimen in place and protect it from accidental contact with the microscope lens Chemically-resistant glass for use in dry or wet mounts for high-resolution microscopes #1 thickness (0.13 to 0.17mm) is precision controlled for uniformity Fits standard 3" x 1" slides for use in most microscopic applications