Review on Hydrotac OPTX 20/20 Stick On Magnification Bifocal Lenses - Reusable +2.50 Diopter (Pack of 2) by Renee Robinson

Given the many conflicting reviews I've seen about whether they will actually stick to your mask and whether it will hold up after rinsing the mask a few times to prevent fogging, I wasn't overly optimistic. I followed the best instructions I found on the internet (not the packaging) to the tee - rinse the mask thoroughly with toothpaste/brush, rinse the mask well and dry completely, soak the self-adhesive lenses in warm water, put them on inside bottom corners stick convex side up/away from mask lens (concave side down), press firmly and blot residual moisture, press firmly again, leave to dry overnight. quite good by anti-fog cleaning and mask cleaning. Two dives that day, then three dives a few days later and they were still going strong. Worked great! I was able to see my computer/instrument and camera settings clearly and also see the sea life perfectly from afar. You can see how great it would be for snorkel masks. Made my diving experience perfect!