The ZoneBridge (BR100) can do several useful tasks. Firstly, it is a transceiver and it can be the piece which connect to your router and acts as the gateway for the Sonos system to tap into your network and access sources. This frees up the other Sonos pieces to be located wherever you need them in the home. Secondly, the ZoneBridge can assist with creating better house-wide propagation of the wireless signals by acting as a relay or repeater. If you are having any reception issues in a part of the house, adding a Zonebridge can help. In fact, the more pieces of Sonos you have, the better your wireless network coverage will be, since they are all backing up the signal to one another.