Photochromic lenses can darken automatically in sun and restore to be clear indoor. I am not quite understand the type you mean. But as far as i know, Firmoo.com provides two type of Photochromic lenses according to color: grey and brown. If you want to know more about the photochromic lenses on Firmoo.com, you can have a look at : http://www.firmoo.com/prescription-sunglasses.html Hope this can help you.