ANTI FOGGING AND NO LEAKING: snorkeling set use the most stable dry floating valve design,and the flexible breath tube is easy to breath and drain,the diving mask is made of tempered galss lenses which can prevent strong ultraviolet rays,and the lenssurface has been specially anti-fog treatment. CLEAR LENSES AND PANORAMIC VIEW: This mask features a single layer of tempered glass lens designed for snorkeling,swimming and scuba diving,the skirt is made of soft hypoallergenic transparent silicone,the ultra visibility provided by the single lensand the unusual shape of the frame extend in all directions. FOOD-GRADE SILICON MATERIAL: Scuba Diving Mask is made from soft transparent or food-grade silicone,and comes with great comfort,The skirt of eco-friendly materials won't make your face allergic,and it's easy to clean after use,especially suitable forlong-term use in free diving,without feeling uncomfortable.