Andux Land Adult Professional Scuba Freediving / Diving Mask Dry Snorkeling Set 4mm Tempered Safety explosion-proof lenses, safety clear transparency of 99.9% Frameless design reduces weight and teardrops shapes provides better view of both upward and downward,1.5 times larger vision . The fully submersible dry top snorkel with one way purge valve. Quick disconnect and rotatable retainer design easily make accommodation of snorkel from mask 100% Submersible Snorkel with ""Pivot Dry Technology",Silicone purge valve for easy draining. Ergonomically precision high light abrasive design can fit different people's faces.