DivePRO Alien Alloy Mask Black The new version of the DivePRO Alien Alloy Mask not only looks cool, it features an extremely low volume, plus sets standards for fit and performance. The DivePRO Alien Alloy Mask features a large field of vision. Alien alloy and other materials used for the average mask require a thicker frame to remain stable. Using aluminium allows the silicon frame to be produced with a very low profile while still supporting a twin lens design. Twin lens design is preferable over single because it brings each lens closer to the eye for a wider field of vision and reduced inner volume. Aluminium also allows for a very minimal centre pillar. The slim-line centre pillar is narrow enough to have almost zero effect on your field of vision.