Calabria Hydrotac Dive OPTX 20/20 Stick On Bifocal Lenses Used for Scuba Masks/Diving Goggles Magnifying Bi-Focal Stickers

I followed the instructions applying them, and did it two weeks in advance of my dive. I did not like my original position, so a week later I followed the steps to remove and position.A week later on dive day, these were well tested during the dive (unintentionally), as my dive mask itself was not a good fit and I spent the entire dive clearing my mask at 44 ft. Stuck on like glue.Power was true to my bifocal prescription, so function as well as I could have hoped (could read my GoPro settings underwater - when my mask was not flooded, of course).Good value opposed to a prescription mask, considering I only dive twice a year.

Didn't really work as I had hoped especially for the price. They are smaller than expected. They did adhere to the mask and stayed in place. Unfortunately they hindered my vision more than improving. Obviously it was a longshotwhat, I mean what can you expect from stick-on readers. My review is more directed at the dive-targeted hype, the actual size and the price for a product that works as poorly as the cheap ones

UPDATE: Some reviewers have said that these lenses did not stay put. I've now had 12 dives with them, they're still firmly in place after multiple mask washes, multiple (and intentional) mask floodings to see if I'd lose one or both. Neither lens has moved. It may be that after installing them as directed I waited several weeks to give them time to stick, but I'm not sure. My only gripe is that these are on the smallish size so I have to tilt my head way back, or raise my gauges up quite high, to get things in focus.ORIGINAL REVIEW: I have crummy eyesight up close, and now that I'm returning to SCUBA I needed diopters to see my gauges and dive computer. I didn't want to pay for prescription lenses, at least not yet, so I tried these. The instructions are clear. These are supposed to be applied with the concave side down, but it was a bit hard to tell which side that was because the curvature is so slight.I put these on as directed after cleaning the inside of the mask. It was fairly easy to "milk" the water from under the diopters but no matter how hard I tried a tiny corner of one of the lenses would not stick down. Hope that's not going to cause problems down the line. I've let these sit to dry for several weeks after putting them on, a dive trip is coming in a few weeks, and if one or both of these fall off I'll be back with an update and modify my overall rating accordingly.

I'm new to scuba and needed something so I could read my pressure gauge and dive computer. I wear glasses with progressive lenses and found that under water, I could see things beyond arms length pretty well due to the magnification the water provides, but I couldn't read my gauges. I didn't want to commit to buying a prescription mask yet.I bought the 3.0x stick-ons and:- washed the inside of my mask with oil free soap - I used plain dish soap as it removes grease and oils- thoroughly rinsed out all the soapy water- put warm water in the mask and dumped it out leaving the glass wet- wet the stick-ons and positioned them in the mask. they slide around easily so I had to be careful as I pressed them down to squeeze out excess water from between the stick-on and the glass- I then dabbed the inside with a towel to remove excess water and let the mask sit for 3 days before divingThe stick-on lenses stayed in place and I was able to read my gauges and computer. Have to remember that readers are for things that are less than arms length away. They're not for distance. Using primarily my left eye, I took my time to hold the gauge or computer in line with the reading lens.I have since moved the lenses to a different mask and have completed another dive without issue.

Instructions say to put the "concave" side towards the glass of the mask. This must take much better eyes than mine to determine which side that is, which is unfortunate bc this is obviously for those of use with compromised close-up vision. I installed just before my last dive trip and apparently guessed correctly on one and not the other. One became loose on my second dive and I removed and saved it to re-install later (still haven't done that.) But the one that did stay on worked great. Was able to read my wrist dive computer and pressure gauges with more clarity, which was nice.

I was on a dive in October and a fellow farsighted diver recommended these “stick-on” cheaters for my mask to make reading my computer and gauge easier. I had no trouble installing these. I was a bit nervous on my first dive that they'd wash right off, but they stuck tight and have on another 12 dives so far.It's easy to see the small print now. Thanks! The only drawback is my dive guides sometimes think I’ve got water in my mask and can't clear it.

The came scratched right out of the box and don't stay in place. Good luck finding the "concave" side to place against the glass. They don't do much good if they fall out as soon as they get wet. By chance I found one of them floating on the bottom of the pool. I won't be recommending them to my studens.

The good thing is that it works great if you follow the installation instructions correctly. It worked on my Mask and full face mask. Didn't have time to get my prescription mask before a trip and this saved the dive.