High light tansmission, high quality BK7 triangular glass blank 98.5X49.5XT10mm 1, Techniques of Optical lens: by Molding, Grinding, Polishing 2, Shape of Optical lens: Plano lens,bi convex lens,bi concave lens, ball lens,Spherial lens 3, Inside quality of Optical lens: clear and transparent, no mold marks, no inside bubble and dirts, 4, Function of Optical lens : Lighting splitting,magnifying ...