This is the Mares Ergo Silicone Dry Snorkel with Exhaust Valve and Ergonomic Design Features: Anatomical design Exhaust valve Corrugated hose and mouthpiece made with high quality silicone The new ERGO snorkel family was designed for maximum performance both for scuba divers and snorkelers alike. From one end to the other, the ergonomic shape fits perfectly to the side of the head. All three versions have a corrugated flex hose made using high quality silicone and features a snorkel keeper which can be adjusted in many positions. All three have an exhaust valve in the mouthpiece for prompt purging. The mouthpiece is molded in soft rubber for greater shock and wear resistance, also to properly host the exhaust valve. Exclusive engineering of the dry top (patented) and an ergonomically correct mouthpiece make this the ideal snorkel for scuba or for prolonged snorkeling sessions. The combination of the 100% dry top and an exhaust valve in the mouthpiece ensures a completely dry breathing environment.