Works with all music and karaoke apps Bluetooth for wireless audio streaming from compatible devices (external devices not included) Six Voice-Changing Effects: Echo, Male, Female, Robot, Chipmunk and Radio Record and playback function Line-in to connect to your personal smartphone, tablet, MP3 or other audio devices 2 microphones for duets Dedicated microphone volume control Auto Shut Off AC/DC & Battery operated (optional) (4 x “C” size - not included)