Tested with batteries (not included). It has independent tempo and key controls, allowing users to change the tempo by up to 50% and the key by one octave without changing the other. It includes a built-in speaker, a headphone jack, and analog and digital stereo outputs. The device can reduce the volume of the vocal track on a CD and has an input for a microphone or instrument, which can be mixed with the CD sound. It is compatible with CD, CD-R, and CD-RW discs and can display CD-TEXT if available.