Cetatek aquabionic S02 Dry Top Flex Purge Snorkel Breathe dry; patented valve at top of snorkel keeps splashing water from entering breathing tube Large-bore oval tube is easy breathing and streamlined to reduce drag One-way purge valve offers near-effortless clearing and a very dry mouthpiece Flexible corrugated silicone lower tube and soft mouthpiece reduces jaw fatigue Includes swiveling quick-release snorkel keeper for fast and easy one-handed attachment and removal from mask strap