1.This snorkel set is perfect for the whole family. The snorkel mask features infinitely adjustable headbands and a highquality silicone face shield that adapts to almost any face shape and is suitable for both women and men. 2. The silicone seal can form a comfortable waterproof seal, no water leakage. 3. Circulating natural breathing: The snorkel mask allows you to inhale the water through your nose or mouth. Breathing is calm. 4. Breathing system: Our onesided (external) recirculating snorkel mask mechanically isolates exhalation and inhalation. Inhalation is via the double breathing tube, exhaled carbon dioxide and the remaining uninhaled oxygen flow out of the human body on the outside of the mask.