This premium fused silica wafer from Corning 7980, Grade 0F, delivers excellent optical quality and mechanical precision in a large, thin-format optic. With a diameter of 200 mm and a thickness of just 0.70 mm, it offers a substantial clear aperture (~85%) while maintaining tight tolerances and minimal distortion. The optic is polished to a cosmetic standard of 40/20 scratch-dig, with fine edge grinding and safety bevels to protect edges.