We are often asked for 'wireless speakers' by customers visiting our retail store, often as many times as I have fingers on a Saturday! Through gritted teeth, we explain that wireless speakers can only exist if batteries are the power source, or some other form of zero emission power such as solar or wind....then we explain that this Sonos S5 speaker is the closest we have come to finding a truly good sounding stereo speaker unit with only one wire - the mains cable. This allows you to position it anywhere in your home, or even on the patio in good weather and a power socket!