1. WIDE FIELD OF VISION------ 180° field of vision and shatterproof polycarbonate window for added safety. 2. Anti-fogging------Exclusive breath ventilation concept prevents fogging. 3. Impermeability / seal------Dry Top snorkel system stops water entering through the top of the snorkel. 4. Water drainage------Purge valve at the bottom of the mask to drain water when the head is raised. 5. Easy dressing------Adjustable elasticated textile strap does not pull your hair out. 6. Visibility------Snorkel top can be seen from 4 times further away than a traditional Snorkel. 7. Swimming depth------Reminder: Surface mask, not suitable for free diving. This full dry snorkeling mask set your hand free, offers a unique diving experience to users allowing them to every breath-taking underwater scenes. The innovative dry top technology enables you to breathe freely underwater. Full face design with tempered glass provides better protection for your face. It is the best mask for you to enjoy your diving experiences! Available Children Snorkeling Mask for 7-18years old  ADULT Snorkeling Mask Features: *Double air-flow channel - inhaling and exhaling separate channels for anti-fogging. *Broadside dual sealing design is from imitating human face, made of liquid silicone without skin irritation. *180 degree wide viewing with anti-impact safety window for good vision. *With a breathing tube with dry top technology, you can breathe freely underwater. *Drain value in the mask, to drain away the water by raising up your head when water leaking. *Adjustable elastic fabric headband, easy to wear and suitable for all kinds of head shape. *Ideal for diving, swimming, snorkeling and other underwater activities