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 (15% 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.