Note these are factory seconds, some units may have one or both line inputs not working. Get quality controlled version from here : https://www.amazon.com/Karaoke-Mixer-Microphone-Stereo-Balanced/dp/B01H66TT52</br>Full metal case. Runs for more then a week on a 9v battery (battery clip provided), or use wall AC/DC adapter (DC 9 to 20v, 2.1 mm positive tip)</br>2 balanced microphone inputs (can amplify instruments as well - balanced or unbalanced lines)</br>stereo RCA input - play from your iphone, android, table, computer, cd player, etc.</br>stereo RCA output.</br></br>Product Description</br></br>Studio quality karaoke mixer. Sing Karaoke ! This mixer is ideal for Karaoke - it has volume controls for the microphones and a volume control for the music. The microphones both come out in stereo. For highest sound quality use balanced connectors. Unbalanced also supported. This is a great unit made of solid metal. Plug into the wall or use portable battery clip (battery clip provided). Use the mixer with the battery clip for portable Karaoke. These mixers are studio quality - very clean signal. Supporting balanced or unbalanced connections. The frequency response is EXTREMELY flat over all frequencies - this ensures that you get a very clean signal through the mixer.</br><br/>http://www.amazon.com/gp/product/B016TXSLHK