This is the Mares Ergo Flex Silicone Snorkel with Purge Valve Ergonomically Designed Features: Value priced and built rental tough Streamlined design is ideal for freediving Silicone mouthpiece and smooth-bore flex tube Comfortable curved mouthpiece design Ergonomically designed for comfort and function Silicone purge allows effortless clearing and prevents water from seeping inside A peculiar feature of the Flex version is the corrugated hose, which is made of transparent silicone. Ideal for those who prefer a simple, yet functional snorkel.