Cressi Air Dual Lens Crystal SCUBA Diving Mask has a particular tapered structure deriving directly from the highly popular Nano-mask patent. DUAL INTEGRATED FRAME- allows you to join the silicone skirt to the lens frame without major interruptions of the curvature continuity. THE PERFECT MASK- Extremely hydrodynamic shape and, visibility being equal, a significantly smaller size. GREATER FIELD OF VIEW- The field of view obtained is particularly wide, laterally and in the lower zone.