PhotoMatic??? lens automatically adjusts to the changing light conditions to darken or lighten depending on the amount of sunlight or UV exposure. Reaction time is 7 to 10 seconds, and the transmission shift is from a Category 1 (85% light transmission) lens, to a Category 3 (22% light transmission) lens. An advanced crystal is embedded in the lens resin that reacts with the intensity of the sun to create the change. The lens material is grade A polycarbonate resin for superior impact resistance with 100% UV protection and Focalpoint??? lens technology for class one optical standards. All Photomatic??? glasses feature non-slip Tactilite??? rubber components & active lens venting. . ??. . . . This product will be shipped directly from Liberty Mountain and will leave their warehouse in 2-3 business days. Eligible for UPS ground shipping only. . ??. . . . . . 100% UV protection. . Grade A polycarbonate resin for superior impact resistance. . Non-slip Tactilite??? rubber components & active lens venting. .