Transitions® XTRActive™ lenses are the darkest everyday photochromic lenses on the market. They offer superior darkness in hot temperatures, thus delivering excellent sun protection for those who spend a lot of time outdoors. In addition, these lenses offer a slight tint indoors and activate moderately behind the windshield of a car. Transitions® XTRActive® lenses are the darkest everyday photochromic lenses on the market. Lenses darken to 85% opacity in direct sunlight. Inside a car, the lenses darken to 30%, and indoors there is always a 20% tint. Transitions lenses block 100% of UV rays. For more information, visit our Transitions lenses FAQs or the Transitions website.