Detailed Product Description Progressive lens(Optical lens)Material: white from Great Lake, Photochromic from LGRefraction index: 1.499 1.56, 1.61Power range: -3.00 to +3.00, Add: +1.00 to +4.00Corridor: 12mm, 14mm, 17mmCoating: UC, HC, HMC, EME availableFinished and Semi-finished availableSemi-finished progressiveBase 4, 6,8