Very good product and I give it 4/5 because it needs a little more quantity, not one drop but definitely 2-3. Then you leave it for 1-2' and then rinse it in the sea with strong strokes

Works great. You put on a good amount, spread it with your finger, let it dry for about 10 minutes, and then dip it a little in the sea before you go in (without rubbing it with water), and you're ready. It works flawlessly for me.

Excellent product, it was recommended to me by a specialized diving and marine equipment store, I bought it without hesitation and so far I am absolutely satisfied. I put 3 - 4 drops on the inside of each lens for a few minutes (as I was advised) and leave the mask aside until I put on the rest of my diving suit and equipment. After I finish this step, I rinse the mask, put it on and start. I can tell you with absolute certainty that I have done freediving for over an hour and a half to two hours and the mask did not need to be rinsed or taken off at all, as the lenses remained crystal clear without a trace of fogging!. I have not used any other product for this job so as to have a point of comparison, but I think I won't need to either, as with this one and only purchase I have been absolutely satisfied.

It does its job just fine. I apply it before I start and rinse the mask in the sea. It's also good to splash some water on our face before putting on the mask.

I have been using it for years, especially in winter.

With an amount smaller than a lentil, I have never seen the mask fog up

It does what it says, it's just very thick and sometimes it's not possible to apply a small amount. I have seen some other spray forms that also seem functional. In any case, the mask and goggles I use do not fog up!

The best thing to prevent the mask from fogging up. I have been using it for several years. It is quite dense compared to others and you won't have any problems until you rinse the mask.