The 61690 plano-convex infrared lens has a diameter of 2.5 in. (63.5 mm), edge thickness of 9.91 mm, focal length of 10.0 in., and is N -Tanaka OEM compatible. The Duralens™ AR coating used for these CO2 laser lenses is designed specifically for 10.6 micron wavelength. The high quality coating increases the amount of energy going through the lens and decrease the absoption to <0.20%. The Zinc Selenide substrate's low absorption coefficient makes it a perfect candidate for focusing applications using high power CO2 lasers. These lenses are designed for high durability and accuracy and manufactured by automated CNC technology to assure complete uniformity. In most laser cutting machines, meniscus lenses are used because they produce a smaller focus diameter.