Now you can sit on the beach and read that great book you brought along. Adaptor Readers darken to reading sunglasses in just seven seconds! Move into the shade or inside, and they change back to clear reading glasses once more. 100% protection from UVB rays when darkened. Comfortable spring hinges fit average to wide faces. Black/silver frame, gray lenses; includes a handy travel/storage case. Choose from +100, +150, +200, +250 strengths.