Missing here is Hawaii's biggest snorkel outfitter and only snorkel company to design and develop its own masks and snorkels, Snorkel Bob's, with a record of 0 (zero) fatalities in over 30 years of business. Give peace a chance. No other mask and snorkel manufacturer in the world is mere steps from end-use consumers going into the ocean. We have the largest beta testing program anywhere, and we learn immediately what needs refining. While aerobic/pulmonary complexity can occur anywhere, any time, snorkeling has more CO2, a hazard for some. The MoflO2 snorkel is patented, delivering fresh air to avoid gray breathing. This report references dead air space but fails to define it. While a regular snorkel triples dead air space, the full face snorkel goes about 1000% over. We won't carry it ever. Please take comfort in a company that takes care to deliver a reef experience with aloha and pono approach to customers and reefs alike.