Visibility is the most important aspect of any dive. The M1 mask raises the bar for optical quality and distortion free vision. This lens is an extra clear glass which is valued for its attractive appearance and optical qualities. The low iron content produces a higher light transmittance and a reduced green tint inherent in other glasses. This makes the lens distortion free and helps improve color and visibility in low light conditions underwater. In addition, this M1 mask also comes with an exclusive Oceanic snorkel. Introducing the Ultra Dry 2. This sleek new ergonomic design incorporates Oceanic's patented Dry Snorkel Technology, drop away flex mouthpiece, oversize purge valve for easy clearing, and replaceable 100% liquid silicone mouthpiece into a comfortable and functional snorkel ready for any adventure. Mask Defog 2oz drop bottle