Thomas 25CIR-1-602757 Glass Circle Cover, 25mm Diameter, No. 1, Thickness 0.13 to 0.17 mm, 1oz Box Circular cover slip for use in cell and tissue culturing Corrosion-resistant glass for use in dry or wet mounts for high-resolution microscopes Thickness is precision controlled for uniformity Slip conforms to Interim Federal Specification NNN-C-001434A