| 摘要 |
Fresh Air Snorkel For Divers A fresh air snorkel comprising a mouthpiece and an air tube, the air tube being divided into a separate inlet tube and a separate outlet tube, each of the tubes being provided with at least one, one-way valve in its free end, which valves are mounted so that fresh air enters only the inlet tube upon inhalation and stale air enters only the outlet tube upon exhalation.
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