At its most basic, a device that records and plays back audio loops. In most cases, a loop can be recorded (often using footswitches for hands-free control) then additional overdubs can be added in stacked “sound-on-sound” fashion. Some loopers offer a wide array of extended features, such as MIDI tempo sync; playback of multiple independent loops simultaneously; reverse loop playback; preset-recall of loops; timing quantization; built-in metronome or rhythm tracks; microphone- and guitar-level inputs; phantom power; USB port or memory card for saving, backing up, and transferring loop data; import/export of loops as WAV files, real-time control of playback speed; and much more.