The ATOMIC AQUATICS SV2 snorkel is a great choice for rough and choppy waters. This snorkel combines an exhalation valve at the bottom and an effective semi-dry top. A one-way drainage valve takes care of water drainage. The water that flows over the top of the snorkel completely bypasses the mouthpiece and flows out through the drainage valve. If there is more water, it enters the inner tube located inside the body of the snorkel, which has a small drainage valve, so that the water flows around the mouthpiece. The diver can easily maintain a dry inner tube by exhaling gently, as only a slight amount of overpressure is required.