Mares X-Vision Liquidskin Two Window Mask is a great choice for vision underwater. With the addition of Mares patented Liquid skin technology, the X-Vision now offers comfort that was formerly impossible. By co-molding two different types of silicone, there is no longer a need to compromise comfort in order to support the frame structure of a mask. The support structure and the area of the seals are molded with a silicone that is 30% harder than the traditional material. The extremely soft silicone portion rests on the face delivering a new level of comfort.