The Xtrainerz ship this spring for $150.

Every so often someone asks me what headphones they can use while swimming. The small list of viable options is about to get bigger with the arrival here at CES of the AfterShokz Xtrainerz (pronounced cross trainers) MP3 headphones. They use bone-conduction technology to transmit sound to your ears through your cheekbones. They'll ship this spring and will cost $150, with no word yet on international pricing. 

Because Bluetooth can't pass a signal through water, like other "swim" headphones the key here is that these guys have 4GB of built-in memory to store your MP3 music files directly on the headphones. Alas, there's no Bluetooth mode, so you can't stream music to the Xtrainerz from your phone. 

The Xtrainerz are designed for underwater use. 

Here are the Xtrainerz' key features, according to Aftershokz:

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