Coverslips
A cover slip is a thin, flat sheet of glass of a transparent material, usually square or rectangular, about 20 millimeters (4/5 inches) wide and a fraction of a millimeter thick, placed on an object viewed with a microscope. The object is usually placed between a cover glass and a slightly thicker microscope slide, which is placed on the platform or slide holder of the microscope and provides physical support for the object and slide.