The R501BT is a versatile 5.1 speaker system providing end users with multiple audio input options, coupled with great audio output. The R501BT is a versatile speaker system, with the ability to be connected to multiple audio sources using the 5.1 input, dual stereo input ports or even Bluetooth. In addition, listeners can also connect a preloaded SD card or USB flash drive to the corresponding input ports for quick, easy, plug and play audio.