Full-face snorkel masks use an integral snorkel with separate channels for intake and exhaled gases theoretically ensuring the user is always breathing untainted fresh air whatever the respiratory effort. They come with a built-in dry top snorkel system. In addition to a standard ball float system that stops the water from entering the tube when submerged, full-face masks are designed in such a way that even if a small amount of water does get into the snorkel, it will be channeled away from the face and into the chin area of the mask. A special valve located on the bottom of the chin allows to drain the water out. The main problem is that it must fit the whole face well enough to make a reliable seal and since no two faces are the same shape, it may not seal adequately on any specific user. In the event of accidental flooding, the whole mask must be removed to continue breathing. Unless the snorkeler is able to equalize without pinching their nose it can only be used on or within several feet of the surface, since the mask covers the nose with a rigid plastic structure, which makes it impossible to pinch the nose if needed to equalize pressure at greater depth. Trained scuba divers are likely to avoid such devices, however, snorkel masks are a boon for those with medical conditions that preclude taking part in scuba diving.
Full-face snorkel masks use an integral snorkel with separate channels for intake and exhaled gases theoretically ensuring the user is always breathing untainted fresh air whatever the respiratory effort They come with a built-in dry top snorkel system. In addition to a standard ball float system that stops the water from entering the tube when submerged, full-face masks are designed in such a way that even if a small amount of water does get into the snorkel, it will be channeled away from the face and into the chin area of the mask. A special valve located on the bottom of the chin allows to drain the water out. The main problem is that it must fit the whole face well enough to make a reliable seal and since no two faces are the same shape, it may not seal adequately on any specific user. In the event of accidental flooding, the whole mask must be removed to continue breathing. Unless the snorkeler is able to equalize without pinching their nose it can only be used on or within several feet of the surface, since the mask covers the nose with a rigid plastic structure, which makes it impossible to pinch the nose if needed to equalize pressure at greater depth. Trained scuba divers are likely to avoid such. devices, however, snorkel masks are a boon for those with medical conditions that preclude taking part in scuba diving.