The Roadster is a complete noise reduction technology solution hands-free carkit. The full deplex sound and quality and auto-answer function means you stay firmly in control when driving. The powerful mcrophone and speaker are located on the fornt of the unit. No installation required. Place mobile phone into cradle. Insert hands-free unit into the cigarette lighter outlet. If you have a recessed, or low on the dash, cigarette lighter outlet, you can use the cigarette lighter extension to bring the mobile phone closer to you. The extension is supplied with this unit. For full duplex mode use the external microphone. Plug the connector of the microphone into the jack located on the right side of the unit and clip the microphone onto your shirt. You can regulate the speaker volume either by the volume control on the hands-free unit or by the volume key on the mobile phone. This unit does not come with wireless headset.