Quality good product.
It needs tightening on the face to prevent water from entering through the forehead.
It generally fogs easily because when you exhale, air passes through the space of the glass. One solution is to tighten it even more, but it becomes very tiring.
It distorts the vision a bit and prolonged use can cause dizziness and headache.
Exhaling underwater is difficult compared to a classic snorkel, but not tragic.
The bubbles from exhaling pass in front of the field of vision, resulting in not seeing anything at the moment of exhaling.
Due to its volume, this specific mask has much more buoyancy than the classic ones.
Finally, the visibility is not 180º because the side windows underwater turn blue.
In short, it is a very nice mask for observing the seabed, even for people who cannot use the classic mask with a snorkel due to its ease of use and the large amount of air provided, but it is not suitable for underwater activities such as spearfishing.