It's mono Bluetooth. It's stereo Bluetooth. It's both.

Jabra's BT8010 expandable stereo Bluetooth earphones

Sometimes you chat. Sometimes you listen to music. Sometimes you alternate between the two on your music phone. And sometimes you alternate between the two using two different devices. Oh, why can't there be one Bluetooth earphone to handle all these situations?

Well, there is--the Jabra BT8010, to be released in the next couple months. First, it's a regular, single, over-the-ear Bluetooth earpiece with an OLED display that shows caller ID. You can also transfer up to 30 contacts to the headset in case you don't want to reach for your cell phone to make a call. Jack in the second earpiece and now you have a Bluetooth 2.0 stereo headset with AVRCP--Audio/Video Remote Control Profile--that lets you pause, skip, and reverse from the headphone (assuming the music device is equipped with the AVRCP profile).

But even better, the BT8010 ($149) earphones can connect to two Bluetooth devices simultaneously, such as a phone and a music player equipped with Jabra's A120S stereo Bluetooth adapter. You'll be able to talk for up to 10 hours or listen to music for up to six hours on a charge, or keep 'em in your pocket for nearly two weeks of standby tine.

The one drawback to this dual earpiece arrangement--one more small gadget to charge and then lose.