Optic Nerve Squeezebox Sunglasses include 4 sets of lenses and come in two colors. All Interchangeables come with a hard case except Caption All Interchangeables are Nonslip construction All Interchangeable glasses have Active Lens venting Except Caption Interchangeable lenses SmokeMirror Bright sun conditions, 18 light transmission RoseCopper General to variable conditions, 26 light transmission Amber b