You'll get the most out of your music collection with the DEH-S4000BT. Tune into the FM radio, listen to a CD or connect your smartphone (and other music devices) via the front USB or Aux-in. On top, you can make hands free telephone calls in high detail, thanks to the external microphone supplied with the product. The stereo even allows you to connect up to two Bluetooth devices simultaneously! For those wanting extra Bluetooth features, you can also stream your favourite tracks wirelessly to enjoy crystal clear playback thanks to the Advanced Sound Retriever for Bluetooth. Enjoy pristine sound from the DEH-S4000BT's built-in amplifiers that deliver 4 x 50W of pure, proven MOSFET power. If you want more power, you can use the 2 RCA pre-out to hook up a subwoofer or an extra amplifier for the rear speakers.