Specimens observed on a microscope slide are typically covered by a coverslip, also known as a cover glass, which is typically composed of thin pieces of borosilicate glass. For the best photomicrography results when using "dry" objectives (no immersion oil) at high magnification, the thickness of the coverslip is essential. 24 x 60mm. 5 x 100 pcs. Thickness: 0.13 - 0.17mm