Specifications£º Material: Bk7, Quartz, Caf2, Sapphire etc. Diameter: .OD:2mm-120mm Edge thickness: 1mm +/- 0.10mm. Focal length: 0.1% to 2% . Surface quantity: 80/50 to 20/10 . Centration: 1 to 3Arc minutes Fringes: 1 to 5 Clear Aperture>90% of diameter Coating: Uncoated, AR, HR, PR coating, etc. Shaps: Spherical, aspheric, ball, plano, cylindrical etc. Applications: Lighting ,project,viedo projector,saolar system,telescope, etc.