Custom-fit and vehicle-specific wiring harnesses included in every Bluetooth kit makes for quick and easy installations normally involving no cutting or splicing of existing vehicle wiring | Full Duplex Digital Signal Processing of audio by every Bluetooth system means you are assured the very best sound quality throughout every phone call or every streamed song | Utilizing the internal memory in every Bluetooth module allows for the memorization of up to 5 different cellular phones! Extra phones can be added in just a few short steps, if needed | With the single-button volume control built into every Bluetooth control switch, the audio playing over your vehicle's speakers is centralized, easy to find and easy to use | Phone calls already in progress are transferred between the Bluetooth module and your cell phone seamlessly when your vehicle's ignition is turned on or off