Line Mixer, Audio Combiner, Line and Stereo RCA Full metal case Runs for days on a 9v battery (battery clip provided), or use wall AC/DC adapter (8.5 to 20v, 2.1 mm positive tip) 2 line inputs (instruments, not microphones, for mics. go here http://www.amazon.com/Karaoke-Mixer-Microphone-Stereo-Output/dp/B00DKDG9RW) stereo RCA input - play from your iphone, android, table, computer, cd player, etc. stereo RCA output