A Snorkel that is Easy to Clear is Low in Profile and one that stays Dryer inside is what you are looking for. SV stand for Scupper Valve, also known as a One-Way-Valve. Just like the One-Way-Valve in your Regulator which when you exhale drains water from your regulator the Scupper Valve basically works the same.
The SV1 uses an additional feature that keeps water away from your mouth a Small Tube located just below the Mouthpiece is designed to keep the Breathing Airway path Free of Water Droplets. The Flexible Lower Tube makes the Atomic SV2 Snorkel perfect for Scuba by Automatically-Swinging Out-of-the-Way when you are using your Scuba Regulator. So if you hate to use a snorkel, but want more bottom time this is the solution you are looking for. Snorkel comes with a Quick-Release Snorkel Keeper that has a 30° Rotation/Sliding Adjuster and has a Removable and Replaceable Silicone Mouthpiece. The Atomic SV1 Snorkel is available in Multiple Color Choices and is covered by a Limited Lifetime Warranty.
The Atomic SV1 Snorkel is commonly used for SCUBA Diving, Snorkeling, Spearfishing, Vacation and more. The Atomic SV1 Snorkel is most used by customers who consider themselves to be a Advanced among others. The Atomic SV1 Snorkel is popular because customers like the following qualities of the Atomic SV1 Snorkel: Comfortable Mouthpiece, Ergonomic Design, Purge Valve.