From ADJ the ELS481 ELS15 BT multi-functional 15-inch powered speaker features both Wireless connectivity and also a built in MP3 player. Use the Wireless Audio from your mobile device as your DJ platform with the use of running connector cables. The ELS15 BT from American Audio also has a built in MP3 player with both USB and SD card inputs. Some of the features of the ADJ ELS15 BT include: 2-way active bi-amplified lightweight speaker with built-in Bluetooth and MP3 player that offers USB & Memory Card input slots, MP3 player with 6-Button functions and blue LCD on rear panel, Comes with 21-Input remote control (p/n ADJ AUD RC), 11 Preset EQ on MP3 player (Normal, Rock, Pop, Classic, Jazz, Blues, Hall, Bass, Soft, Country or Opera),High power class A/B bi-amplified system designed to perform at maximum efficiency.