Bobster Hooligan Photochromic Sunglasses (Black) PHOTOCHROMIC LENS: The Hooligan lenses are photochromic starting with a light tint (85% transmission) and transform to a medium grey (32% transmission) in bright light. Bobster photochromic lenses are designed to automatically darken/lighten to the amount of ultraviolet (UV) light that reaches the lens. The advantage of a photochromic lens is that you can wear your eyewear all day and not have to carry multiple sets of eyewear with you or change your lenses according to light conditions IMPACT RESISTANT UV PROTECTION: Our Polycarbonate lenses are up to 10 times more impact-resistant than plastic or glass lenses and they also provide 100% protection from the sun's harmful UV rays. They are also lightweight, adding to the comfort of your eyewear Rx prescription ready Comes with protective carrying case