Unigear 180&deg; Full Face Snorkel Mask -Panoramic view with Detachable for GoPro Mount and Earplug,Anti-Fog Anti-Leak Snorkeling Design For Adults And Youth FIELD OF VISION: 180 field of vision and shatterproof polycarbonate window for added safety. EASY BREATHING: Full mask for natural breathing through the nose and/or mouth. Exclusive breath ventilation concept prevents fogging. Snorkel top can be seen from 4 times further away than a traditional Snorkel. Size: please find the size chart from the 2nd picture on the left.