The AV550BT is a powerful 5.1 surround amplifier equipped with Bluetooth, FM radio, USB, and SD card slots. This versatile system is also excellent for karaoke applications, thanks to the two microphone inputs with echo control on the front. The AV550BT features five channels to support all the speakers you need for the ultimate surround sound experience, as well as multiple inputs and outputs for your audio devices and equipment. Play tracks directly from a USB or SD card, connect wirelessly via Bluetooth to your digital library, or listen to your favorite radio stations in surround Hi-Fi sound with the FM radio tuner.