audio system 2 pro audio system offers you the perfect means to bring music into your spa. Simple to install and compatible with numerous audio sources using the auxiliary audio input or play music wirelessly using a Bluetooth mobile device. Listen to music in MP3 format saved on a USB flash disk or tune in to an FM station of your choice using the 2 pro integrated FM receiver. The audio station can be used to charge most mobile devices with its onboard USB charger controller.