If you have to choose between blue and gray lenses, ColorVision Blue Gray is the best option. This lens features a gorgeous pattern and the ideal balance of the two colors. Details of the product material of the lens: Hima 55 55% of the water is water. Base Curve: 8.6 Center Diameter: 14.2 0.04 in thickness Contents of the package: a pair of lenses Use period: up to 14 hours per day for a maximum of two months