Besides the obvious answer being your ear, where else could you keep your Bluetooth earpiece without loosing it?
Well MoGo thinks that the best place to keep this would be right on the back of your iPhone or your BlackBerry, on a small shallow cavity which is moulded into a clip on false back in which the flat MoGo Bluetooth will snugly sit.
The actual earpiece folds down to go in your ear, underneath the earpiece stowage cavity is a USB jack which flips up and enables you to connect your iPhone or BlackBerry to one charger and the earpiece to a separate USB cable without removing the Talk from the phone. Source – dvice.com