Cressi Sub Gamma Scuba Diving Snorkel Profiled guard: this drastically reduces water intake and splashing from the top without blocking breathing. Adjustable attachment: system of quick-attachment to the mask strap, which runs along the snorkel bore for perfect positioning. New drainage well: this draws all the remaining water to the bottom end of the tube, preventing all blockage to breathing. Internal elliptical valve: the elliptical valve optimises water drainage, making it quick and easy to purge the snorkel.