As the name implies, the earphones receive an audio signal via Bluetooth from a separate MP3 player, mobile phone, or other digital audio device - the earphones and that device must be electronically paired with one another before the first use, which users can do themselves.
Any device that is stereo Bluetooth-enabled should be compatible, although Jaybird also sells an adapter for those that aren't.
A built-in mic also allows the user's voice to be transmitted to the device, should it be a phone.
Once the JF3s are ready to go, the only cord that users have to contend with is a short one that goes around behind their neck, from ear to ear.
Because people tend to move around a lot when they're working out, the earphones also come with honey comb-patterned silicone ear cushions.
These are designed to comfortably keep the phones in place, reportedly providing "a balanced amount of resistance against the back bowl of the ear (top, back and bottom)." Each kit comes with three sizes of ear cushions, and of ear tips.
Source: Jaybirdgear
