Increase or decrease in UV rays makes the lens go darker or lighter. This gives a constant and optimum visibility in varying light situations such as driving through tunnels, diverse landscapes and varied weather changes. The lenses are coated with a special layer to prevent any condensation caused by thermal changes Responsetime From light to dark in 8 seconds From dark to light in 35 seconds All Polarized lenses are coated with an anti-static, water-repellent coating