AfterShokz Openswim MP3 Waterproof Headphones - Black Diamond Size:One size fits all A small secure pocket means

A small secure pocket means that any small valuables will be safe

With foot stirrups and a back zip security pocket

Lighter footprint

Designed to follow the natural movement of sport for a better fit and greater comfort in motion

AfterShokz Openswim MP3 Waterproof Headphones - Black Diamond Size:One size fits all A small secure pocket meansWith AfterShokz Openswim 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