Borosilicate glass used as light shade, optical lens, plano lens, auotomobile lens, Sight lens, Front lens, ... marks, no inside bubble and dirts5. Function: Guide of the light beams e.g. Fresnel lens, Plano lens, Bi convex lens ... , Front lens, Refractor, Molded lens, Spot lens, Lamp cover, Lamp shade, Light shade, Light cover, glass cover, glass ...