B&O Beolab 4000 are active speakers you can connect to any product.
For example: Beosound core, Beoconnect Core, Hall audio, Airport express, Google chromecast, Sonos connect or as simple as Bluetooth.
Connections:
2 x Powerlink
1 x Line-in / Rca
Fits very well with Beolab 6000
Fits very well with Beolab 11
If you want a different speaker front, look here
