• A: Optical Lenses(ME80 & ME55 only)
Prescription lenses are available in diopters from -1.0 to -8.0 in -0.5 decrement.
• B: Skirt
Made from the best grade of crystal clear, hypoallergenic silicone, the skirt is soft and automatically conforms to a wide range of facial profiles.
• C: Silicone strap
Mounted on swivel buckles, the strap with its large contact surface secures the mask to the wearer.
• D: Ear covers
The soft silicone Ear Covers forms a water tight seal between the ear drum and the cover. The pressure buffer created to have the same pressure as your nasal cavity mask when air exhaled through the nose is introduced through the Equalization Tubes. Therefore the ear pressure in the middle and outer area is the same and the "squeeze" from the ambient will be significantly reduced. Other benefits from keeping the ears sealed also include reducing the chance of an ear infection from water, plus improved sense of direction and warmth retention.
• E: Equalizing tubes
With one-way valve placed inside each tube, air is allowed to travel only from the mask to the ear covers for pressure equalization and water clearance while stopping water from flooding the mask in the unlikely event of flooded Ear Covers.
．Pressure equalization is easier achieved!
．Prevents pressure induced ear ache (barotrauma)
．Enhanced underwater hearing and sense of direction
．Stops dirty / polluted water from entering the ear causing infection
．Increased warmth around the ear in cold conditions
Available in 6 models: ME80-CB, ME80-06, ME55-BS, ME67-CB, ME67-BS, ME59-CLB (kids' model)
Read more: http://www.k2snorkel.com/product_description.php?category=2&sub_cat=28&product=2359#ixzz1o6h6lQUd