ZnSe is used for optical windows, lenses, mirrors, prisms and optical blanks, plates, disks, sheets, slabs particularly for infrared applications. Zinc Selenide (ZnSe) - transparent in wide spectral range from yellow (visible) to far IR. ZnSe material is a chemically inert, non-hygroscopic and highly pure product that is very effective in many optical applications due to its extremely low bulk losses, high resistance to thermal shock and stability in virtually all environments, easily machined. To obtain superior transmittance, ZnSe crystals are grown by Chemical Vapor Deposition process . Zinc Selenide is polycrystalline material, demonstrates superior CO2 laser transmittance and is employed in the transmission optical components used in CO2 laser processing. Specification: Tolerance of Thickness: ±0.010'' Aperture: 90% of the Diameter Face accuracy (radial deviation / irregularity) at 0.63um: