DOCK Box is the ideal solution to make the iPod part of an audiophile hi-fi system. Dock Box acts like a perfect buffer amp for the iPod and therefore lowers the distortion level significantly. After passing an initial amplifier section, the signal is transferred to the hi-fi system with an impedance lower than 15 ohms. This guarantees trouble-free signal transmission with ultra-flat frequency response and offers the best, most cost-effective way to build an audio system around an iPod. Dock Box Fi Audiophile version with fixed volume level, which is intended for any existing hi-fi system, highly recommended when linked to Pre Box, Pre Box SE, Stereo Box or Receiver Box. Thank you.