Photochromic lens technology helps to darken and lighten automatically in response to changing light. They help you adapt to changing light conditions so you’ll always perform at your best. The lens will allow 87% light through indoors, but only 47% light when outdoors. They also filter out 100% of all UV, even when the lens color lightens to help you see in dimmer environments where UV is still a threat. You get the added benefit of having lenses that aren’t too dark when the sun pulls a disappearing act, or too light when it knifes through clouds.