Ivation Dry Snorkel - Snorkeling with Purge Valve for Easy Snorkel Clearing - for Swimming, Scuba Diving, Snorkeling Premium Snorkel with Silicone Mouthpiece is Comfortable & Very Durable Full Dry Top Prevents Water from Entering Snorkel, Even When Submerged Adjustable Clip Secures to All Diving/Snorkeling Facemask Makes & Models Lower Purge Valve Enables You to Quickly Expel Water from Inside Tube Innovative Pivoting Top Closes Upon Submersion & Opens Upon Surfacing Premium Snorkel with Silicone Mouthpiece is Comfortable &amp; Very Durable Full Dry Top Prevents Water from Entering Snorkel, Even When Submerged Adjustable Clip Secures to All Diving/Snorkeling Facemask Makes &amp; Models Lower Purge Valve Enables You to Quickly Expel Water from Inside Tube Innovative Pivoting Top Closes Upon Submersion &amp; Opens Upon Surfacing