A headphone amplifier based on the popular FLY amp. It has a very compact, pocket size and great sound. The device offers three selectable channels that can cover a wide range of sounds, built-in chorus, delay, reverb effects, and ISF function. The amplifier has a built-in headphone output and a telephone or mp3 player input. It is also equipped with a foldable 6.3 mm jack connector. The device is powered by three AAA batteries and its operating time is 17 hours.