BlueStar install w/pics

[NJ H2]

It's a box type thing you plug into OnStar so you can connect to your Onstar system with any BlueTooth Cell Phone using whatever cell service you have. I have Verizon. It uses the OnStar Mic and Car speakers just like OnStar did. You also should be able to use Steering wheel controls. I can't cause I have an aftermarket head unit.
It works and sounds great though!

Here is the link:
http://costartech.com/pb/products/bluestar.html

and here is a better explanation from their website:

BlueSTAR 2010

The BlueSTAR 2010 is an integrated communications system designed to allow bluetooth communications in your GM vehicle. It works by utilizing the onstar equipment in your vehicle (microphone and mirror keypad) to communicate to a hands free car kit which connects to your cellphone.

There are NO EXTRA CHARGES to pay EVER. You use YOUR phone with YOUR minutes as you see fit.

Better yet, the BlueSTAR is invisible in your vehicle. There are no wires to run, no speakers to install, no microphone to route, and no ugly chrome keypad glued to your dash. And since the BlueSTAR takes advantage of the high quality sound equipment already installed in your vehicle, the audio quality is far superior to other bluetooth options including car kits and headsets.

Make calls, answer calls, mute calls, and transfer calls all using the existing onstar mirror buttons. And if your phone is equipped with voice dialing, you can do it all with the touch of a button.