Cressi Air Crystal MaskAir Crystal Mask Not only has this new Cressi Crystal Silicone been chosen, with its exceptional softness and comfort, but the entire design of the skirt has followed new rules which allow a point of contact between the mask and the face that has a very open angle. The mask rests on the face with unprecedented comfort and does not leave any marks on the skin, even after extended use. Naturally, to obtain such a result the entire structure of the skirt