ON KILLER SALE! Experience the best portable sound coming out of your favorite headphones with the HeadRoom AirHead amp. The little missing link between headphones and your iPod/iPhone, mp3 device or other portable player, the AirHead avoids loading down your player's efficiency to drive headphones with amazing clarity and detail. The AirHead operates via 4 AAA batteries (AC power supply available sold separately) and features our famous HeadRoom crossfeed for improved headphone imaging. Built-in low/high gain switch matches most headphone impedances.More handy info can be found in our Total AirHead FAQ.