Detailed Product Description Mineral photochromic lensPGX, PBXRefraction index: 1.523 Blank: Corning blank(1.523) and China blank is available.Color: Grey and brownAbbe value: 58 & 64Can be used equally well throughout the year, in and out, in all climates and different activities.High original transmittance, high rate of darkening in the sun.AR Multicoating in Green color is available.Corning ...