Editors' note: As of August 2008, this product has been replaced by the Sonos ZonePlayer ZP120.
The Sonos ZonePlayer ZP100 is the amplified base station portion of the Sonos Digital Music System. One ZP100 is included with the BU130 system bundle, but additional units, for expanding the wireless music network into more rooms, can be purchased for $500 each. Because it has a built-in amplifier, standard speakers (such as the matching Sonos SP100 ) can be attached directly to the SP100. For more information on the ZonePlayer ZP100, see the full review of the Sonos BU130 Digital Music System.