1.Dia.112mm 2.Material: borosilicate glass 3. Surface quality: Polished 4.Resist high temperature 5.Glass lens for Light 1.Raw material of fresnel lens: Borosilicate glass, Pyrex 3.32. Processing of fresnel lens: by Molding, Grinding, Polishing3. Quality of fresnel lens: optical surface quality and well controlled tolerance4. Inside quality of fresnel lens: clear and transparent, no mold marks, ...