Hear how something so small but can sound so big Enjoy the rich bass from its Unifying body without compromising on space, Two compact satellite speaker embedded in the both sides of MP505 to deliver balanced, accurate and deep sound with a wireless control. USB Flash drive and SD card Direct Slot The back panel of MP505 are having 2 slot for using USB Flash drive and SD card directly, which means users can just plug USB Flash drive and SD card into the back corresponding interface for direct music playback. Por– Retracand Build-in Lithium Battery For portability, the 3.5mm connector and 800mm cable are made retractable, which saves the space of storing, and highly enhanced the flexibility of MP505. While the outdoor using, the Build-in Lithium battery can significantly prolong the playback time, and provides plentiful energy for the impetus of speaker unit.