When we first saw the Hollis M1 Mask we thought it was just a Hollis branded Oceanic Shadow dive mask - but having gone to the Oceanic seminar and sitting through two days of product knowledge we are much more impressed with the thought, effort and design that has gone into the Hollis M1 dive mask - and the whole Hollis range to be honest.
Due to the Saint-Gobain Diamant - Crystal Clear Lens and skirt being a bit wider than the shadow it brings a much clearer lens much closer to your eyes with obvious benefits of a far wider field of vision, low volume and ultraclear 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.