FINISDuo Underwater MP3 Player - Bone Conduction Swim Headphones - Waterproof Audio - 4GB - MP3/WMA Compatible - 7 Hr

[Edit Oct 2022 after owning 18 months: After charging the unit yesterday, I discovered that the little green square cover on the charging plate had been lost, leaving a glob of glue, exposing the metal plate. Quick response from customer service: it will now leak and be ruined, and the one year warranty is gone. I was offered a discount on a new one. Disappointing, but I suppose 1 1/2 years in the water is an acceptable life for this fun device. I do not know if it is the amount of use or merely the age, but a glued-on part, whether merely left in storage or rubbing against my head and in water cannot be expected to last indefinitely. For now, I plan to either move the loose cosmetic tab from the other side over the charging plate (but what kind of glue to use?), or put a little piece of duct tape over it. That could give it an extended life, I suppose. Also, re my note below where I discussed the advice about cleaning the contacts, I never encountered any build-up on the contacts, so I did not need the calcium remover chemical; furthermore, given the apparent fragility of the glued-on part, I suspect exposing that to any unnecessary chemical attack may not be wise.]I have had my waterproof Finis Duo MP3 player for 5 months, swimming laps in pool 4x/week, and I like it. I have very little previous experience with other listening devices, but I wanted something for this purpose that would allow me to keep water out of my ears. The sound is fine for rock music, and my ability to decipher the words is no worse than a car radio, but it is way more enjoyable than counting strokes to myself.The sound bypasses the ear canal, eardrum and ossicles through bone conduction directly to the cochlea. I wear multi-use disposable silicone earplugs (CVS). Without them, the sound will not be as clear.Bluetooth apparently does not work through water, so you load the MP3 music files onto the unit’s memory directly from your computer, and can delete and/or add anytime (4GB of flash memory). I haven’t used iTunes for this, but one may need to convert iTunes music to MP3. The files I loaded onto my Duo were already MP3 files. I can only guess an MP3 book file would work, too, since I just read that those files are about 280MB for 10 hours; however, I don’t know what I would do if I missed an important sentence and had to go back.Finis company was very good at answering some questions I had via email. I got some tips from reading other reviews, too.You should charge the lithium-ion battery for 24 hours before first use—maybe it won’t hold a charge if you fail to do this the first time.You can charge on a fast charger on wall safely, but don’t store the Duo unit itself on the charger. Battery life claimed of up to 7 hours, though I cannot attest to that. I chart mine every 2 or 3 uses (half hour swims).It took me awhile to memorize the buttons and their use. I’m still unsure when the toggle at bottom is on random play or not, or whether that resets after turning the unit off. I also have another question for the company: Even though I turn it off before connecting to charging, why has it started playing recently when the charging finishes?I suggest looping just one of the 2 straps of your goggles to the unit if your goggles have an overlap in the front. I had to fiddle with this carefully for several weeks before deciding the best connection to avoid the device from lifting goggles off my eyes, while allowing the speakers to fit just in front of the ear over the zygoma, a.k.a. cheekbone. You may prefer to have yours on the insider strap loop, rather than the way I currently have mine (photo).Once I figured this out, I leave the unit attached to my goggles permanently to avoid breaking the clips.I noted a previous review suggested using CLR- calcium, lime and rust remover instead of alcohol, so I bought some, but have not needed it yet. Six hours at full strength as reviewer suggested may be excessive, because it took some of the finish off a faucet I tried it on. Bottle instructions say far less time and at half strength.

This is an update to the review I wrote below. The manufacturer bent over backwards to send me a new device that they had tested before sending me. It worked beautifully for a few months. These were some of my happiest days swimming in my life - the sound quality under water is phenomenal. But then the same problem started again. The device will simply not recognize the contacts in the charger. I can't charge it. I can't transfer musci. It's just dead plastic. I really love this product when it works. Please resdeisgn this so the that the charger contact problem is fixed.************This review is for a defective model - not for all models. I was sent this product as a Christmas Gift purchased by my brother through his Amazon Prime Account. At first it worked beautifully. I do have to say that when it works, the underwater sound quality is AMAZING. But then I started to have all sorts of problems - it wouldn't keep charging when I put it in the charging cradle, it would work in the pool once, but then the second day it would have completely lost all of it's power, even though a full charge should have lasted for hours.I called FINIS directly and gave them my model number, 021115 and was told that this is from a batch with a known defect - that the magnet installed that is supposed to pull the device into the charging cradle securely so that the contacts touch and it charges (or allows you to upload or down load music) simply is defective and doesn't have sufficient magnetic charge to hold tightly. The customer service was excellent and they offered to let me send in my device for testing and exchange. I have elected instead to replace it through Amazon. I am waiting to see if the replacement cures this defect and other odd issues that I have had. (Note - the way the said that this is a known bad batch, sounded like there are other model numbers out there that are also defective. So don't go my just my model number, call and ask if your number might be part of a defective group if you are having problems.)The other odd issues include, 1. some songs don't play well and break up during play, 2. I am not sure if the power loss after one use is due to a low charge or that the device isn't powering off like it is supposed to when I hit the power button, 3. the volume was higher when I first got the device and now doesn't seem to go up to the same level as it did originally, 4. when I push the button to mix the play back, it turns it off completely, 5. The device seems to go back to the top of the play list when I start the next day, instead of playing through the list completely, ie it repeats a few songs all the time and ignores the rest.FYI - to find your model number look on the ear piece just below where you can see the charging connectors. It is written in the middle - on mine it is white letters on the black background.