This 4-channel stereo headphone amplifier offers 1/8" and 1/4" I/O as well as lower noise, lower distortion and more output in a stackable metal case. It lets you easily add additional headphone outputs to any mixer, computer audio interface, workstation, iPod, media player or laptop without creating any additional load on the existing headphone source. Its host of outputs gives you great flexibility for connecting to virtually any source, including studio phones, in-ear monitors, custom earpieces (or all of the above).