I have purchased my ProEar Corona a year ago, after severe otitis ended with eardrum perforation.
First I tested the mask during freshwater spearfishing at the depths 5 - 15 m. It worked very good. However, the mask requires special hood to continue diving/spearfishing in the cold waters.
Recently I have tested my mask in the "real deal" (Red Sea), having reached the 30+ m depths without ANY problems with my ear. I assume my personal maximum in this model would be around 35 - 37 m. However, taking into account that mask itself is designed for the comfortable diving within the 0 - 20 m range, this is very good, too.
The ears were dry during my 2-3 hours daily training. I started to equalise from 6 - 7 m, whereas in the "normal" mask my first pinching is at 4-5 m. The equalisation is smoother. I was pleasantly surprised having not found that the equalisation eats more air than the normal mask, although it should. Further, I did not feel that the mask "sucks out" my eardrums, when the air in the earflaps expands on ascent .
The only problem I can mention was slightly unbalanced equalization of my healthy ear comparatively to the perforated one after -20 m. I assume that the reason for this is the overflow of the air through the perforation, which leads to the "underequalisation" of the other ear. By pinching the respective tube of the mask during the equalisation, the problem was completely solved.
As a result, I have decided to continue my freediving/spearfishing activity with this mask. For those who are interested how to increase the comfortable depth in this device, I can send my humble ideas by email.
Respectfully,