The Cressi Alpha Ultra Dry snorkel allows divers to take every breath with confidence and focus on the reef-below, not on worrying about water in their air way. A generous bore contoured tube provides ample airflow and a lower purge valve enables instant clearing if needed. The Alpha Ultra Dry has the latest dry-top snorkel technology that auto close the tube when submerged for not allow water entry when you go underwater. Once you ascend back to the surface, you can resume breathing without having to make the effort to expel water. The corrugated flexible tube reduces jaw fatigue and the flexible tube allows the mouthpiece to drop away when not in use, making this one great snorkel for scuba divers. The high quality removable and replaceable silicone mouthpiece is comfortable and durable. The mouthpiece is also angled further reduces jaw fatigue. The Alpha Ultra Dry streamlined design reduces drag while snorkeling, and the adjustable clip for securing the snorkel to your mask has its own streamlined shape to further reduces drag in the water.