I ordered this mask for a prescription of OD -6.75 / OS -7.25 and chose lenses of -7 / -7. This was a great level of correction, I was able to see clearly. The mask stayed sealed against my face quite well. I was a little concerned that this might be a bit small for my face, but it was comfortable. For reference, in motorcycle helmets I'm a size XS. I ordered the GearAid sea drops and highly recommend using that on all of the internal surfaces. There was no fog at all when I used it, and the goggles did fog up when I didn't reapply the gel after coming out to warm up/grab a snack and going back in. I was able to use these four times during a week (best vacation of my life!) and they'll be in my luggage next time I get a vacation.
Great customer service from the company and it shipped out to me quickly.