Achromatic lens is designed to limit the effects of chromatic and spherical abberation. It is corrected to bring two wavelengths(typically red and blue) into focus in the same plane. Achromatic lenses can be doublets or triplets, with two or three individual glasses cemented together. Material--------------------BK7 Grade A or equivalent optical glasses Design Wavalength-------480-650nm Diameter Tolerance-------í+0.1mm, í+0.15mm for Dia.í¦75mm Paraxial Focus Length-----í+2% @546.1nm Centration-----------------80% Surface Figure-------------ª-/4 @632.8nm Surface Quality------------60-40 scratches and dig Coatings-------------------Antireflection coatings or NIR coatings Bevel-----------------------A slight protective bevel (For different applications, there are various choices in the specifications, which must be determined according to users specific requirements.) Products include: Achromatic lens Meniscus Lens Double-concave Lens Plano-concave Lens Double-convex Lens Plano-convex Lens Cartons