The Mares X-Vision two-window Mask is a great choice for vision underwater. In just a few years the X-Vision has become a benchmark in diving masks. This product's success derives from meticulous computer design and numerous optical tests. These results have been confirmed by the many replicas and copies of the product. The central position of the eyes and the optimally angled windows provide the widest possible viewing angle in every direction. Field of vision 20% wider than previous version.