I do not understand...
My understanding is that while diving on open circuit, there are 4 relevant gas compartments:
* The compartment that goes from your regulator, through your mouth, down your throat, and into your lungs. Call it the lung compartment.
* The compartment that goes from your upper throat, into your nose, out to the inside of your mask. Call it the mask compartment.
* The compartment that goes from the back of your throat, through the eustachian tubes, up to your middle ear. Call it the middle ear compartment.
* The compartment that goes from the outside world, through whatever equipment you may have on your head, into your ear, and stops at the tympanic membrane (aka the eardrum). Call it the outer ear compartment.
The lung compartment is kept at ambient pressure, thanks to gadgetry inside the regulator. Since the lung and mask compartments are connected by a voluntarily-openable valve, one can keep the mask compartment equalized by exhaling through the nose. Similarly, the valves connecting the throat to the eustachian tubes can be voluntarily opened, allowing the middle ear compartment to be equalized -- this is the part that requires new skills, and some folks have an easy time, other folks not so much. The outer ear compartment is automatically maintains ambient pressure as long as water and gas can move freely in and out of the ear -- ie it is not blocked by a hood, earplugs, excessive ear wax, etc.
As far as I can tell, this product does 2 things: 1) seal off the outer ear compartment so that water and gas can no longer freely move in and out, and then 2) connect the mask compartment to the outer ear compartment, allowing one to clear it the same way one clears their mask compartment.
If the above is correct, then I do not understand the value proposition when it comes to equalizing the ears. With a standard mask, this compartment is equalized for free. When people struggle to equalize their ears, the struggle is with the middle ear compartment, not the outer ear compartment.
However, if a diver is prone to outer ear infections, they might want to prevent water from entering the outer ear, which I could see this product helping out there, since it seals off the ears to water exchange. That seal would create an equalization problem, which I can see how connecting to the mask compartment would solve.
Can someone explain to me 1) what issue this mask attempts to solve, and 2) how the mask solves it? Am I completely missing something here?