I had hip surgery back in January to correct a weird and unsuspected birth defect, and while the operation was a smash success, my physiotherapy regime calls for six months' worth of deep water running, which is pretty much exactly what it sounds like: wearing a float-belt and running up and down a pool full tilt (without touching the bottom) for 40 minutes three times a week. This is as dull as you might imagine, and my physio recommended buying an underwater MP3 player and passing the time with podcasts and audiobooks, which was a swimmingly good idea, as it turns out.
However, buying an underwater MP3 player has been more complex than I'd thought. I started with a Speedo Aquabeat, which is about the worst-designed piece of consumer electronics I've ever owned. Not only does it crash every single time I use it, it also requires some kind of proprietary Windows crapware to create custom playlists if you want to do something really complicated, like listening to all the numbered tracks of an audiobook in order. After the Aquabeat crashed with seemingly terminal finality, I tried something else.
Something else being the Nu Dolphin, a semi-generic Taiwanese device that at least supported complicated use cases like "Play these tracks in order." However, the Dolphin's headphone seal turns out to be pretty fiddly and the second time I used it, it filled up with pool water and died forever. And yes, I did, in fact, carefully screw the headphones all the way in. Go figure.
The third time turned out to be the lucky try: Finis's SwiMP3 is an ugly, clunky, weird answer to the question, "How can I listen to audio in the pool?" but at least it works.
Finis's design is markedly different from Speedo's or the Dolphin: rather than building a waterproof device with a gasketed 1/8" headphone jack for charging and listening, the Finis embeds its controls directly on one of the earpieces, these being sealed, teardrop-shaped pieces of plastic that are intended to be held against your cheekbones by the straps of your swim-goggles. Yes, the SwiMP3 conveys your MP3s to your head by means of bone conduction, which is so science-fictiony it practically sells the product right there.
A wire runs between the earpieces, and midway along that wire is a standard USB plug with a dustcover. It's nominally waterproof, this cover, but doesn't have much by way of a positive clicking lock when you shut it, which leads me to suspect that you can get it wet without killing the device (though the instructions warn you to ensure that it's dry before you plug it into your computer). I haven't tried it, though.
The SwiMP3 shows up on your desktop as a USB mass-storage device (that is, like any USB thumb-drive). You make playlists by sticking MP3s in folders; each folder is a playlist and the files play in alphabetical order (there's also a shuffle mode). Music organizers generally recognize the SwiMP3 automagically -- I've been using Banshee with it, which is handy, since that's also what I use for all my desktop music.
The controls are small, and have a bunch of different functions depending on how you use them -- for example, the next-track button is also the volume-up button (but only if you press and hold it down). This could be better thought through, but I don't do a lot of track management once I hit the water.
How's the sound quality? Well, bone-conduction is pretty top secret, super-spy, but it's no audiophile's delight. Out of the water, it works less well than the in-the-ear headphones used by the Speedo and Dolphin (though unlike these products, the sound actually emerges reliably). Underwater, the sound is actually much improved. I like it, overall -- having my ears free saves me from collisions with other denizens of the pool's slow-lane, who are a blundering, crash-prone lot. And pristine audio quality isn't that important with spoken word, which is what I bring to the pool.
All told, the SwiMP3 is the least-worst product in a pretty amateurish race, but it does have the distinction of being the only product I tried that actually worked.