AVAILABLE ON LINE ONLY. Full internal floatation w/built in ventilation channels 100% glare free Polarized lenses by Polaroid Wrap around frame for side UV protection Case included The floating styles are equipped with Polaroid Polarizing lens, technical name is S13. The support layers of this material is CAB (Cellulose Acetate Butyrate). It is a 7 layer laminate with a high quality scratch resistant hardcoating. The whole lens is presspolished and optically correct, optical class 1, CE standard. CAB has advantages and disadvantages... +unbreakable +99% polarizing efficiency +100% chipping free +optically class 1, power readings and refraction is excellent -fairly scratch resistant 2.5 HD +lightest weight +very good thermal stability -distortion along frame edges possible