TIPS FOR ANTI FOGGING: Actually, most of the snorkel masks in the market are fogging, there's no "100% anti-fog" mask, it's just that some fogging problems are very serious, and some only have slight fogging. An experts who have been producing diving masks for 13 years tell you: you can do some measures yourself to to achieve anti-fog: 1 Before take the snorkeling mask on, try to put the glass in water for a while or spray water on the glass lens, that would reduce 70% fogging. 2 Do not try to breath through nose when your mask is wearing, cause when you try to exhale through your nose, the airflow in your body hits the mask. The temperature of the airflow is equal to your body temperature, and the temperature of the lens is equal to the temperature of the seawater. At this time, the temperature difference will cause the exhaled gas to liquefy into water vapor. Please remember do breathing through your mouth!