AfterShokz Xtrainerz MP3 Waterproof Headphones - Black Diamond Size:One size fits all The outsole has been re-designed

The outsole has been re-designed with stretch web to work and compliment this by allowing boost™ to move and adapt

The back is adjustable for a more custom fit and reflective detailing allows you to be more visible in lowlight

dry and comfortable as you run

Reglan sleeve for freedom of movement

Tactel® inner layer wicks away perspiration to keep feet dry and cool

AfterShokz Xtrainerz MP3 Waterproof Headphones - Black Diamond Size:One size fits all The outsole has been re-designedWith AfterShokz Xtrainerz MP3 Waterproof Headphones you can now have music when you swim as well as when you run. These bone conducting headphones sit outside the ear so you can remain aware of your surroundings at all times. They have the best audio quality for bone conduction technology on the market which means there's no need to compromise on sound, even when you're underwater. The built in MP3 Player has a 4GB memory which can store up to 1200