Whale Dry Diving Snorkel, Liquid Bottle Nipple Silicone Mouthpiece for Snorkeling & Scuba Dive Extremely Comfortable and Healthy Material: Whale snorkel's Mouthpiece and Corrugated Hose are made of very safe, comfortable and durable liquid silicone, which is the same material with baby bottle nipple. Clever Dry Top: When the top of the snorkel goes below the waterline, the floating ball will seal the breathing tube to prevent water from entering. When the top of the snorkel returns above the waterline, it opens again allowing air to move freely. Perfect Breath Tube Design: Whale dry snorkel designed with the 16.8 inch elliptical hydrodynamic tube, not only allow you breath freely and reduce the flow resistance but also avoid too much residual CO2 exhalation. Great PU Tube: Comparing to PVC and TPR tube, PU is a kind of material anti-aging, avirulent, insipidity and tough, No matter how you bend or twist, it would renew as before. Chamber and One Way Purge Vavle: Tere is a small chamber around the one way purge valve to collect water before it is expelled, stopping water from going into your mouth, One way vavle clearing a lot easier and effortless.