Dali - Kubik Free and Kubik Xtra Wireless Speaker System in White Bluetooth and Optical input is just two of the seven possible connection types that the KUBIK system offers 100 Watts Class D amplifier is a true active solution offering a fully digital crossover, direct handling of digital sources, and a high quality AD converter Control and optimize the audio stream perfectly for the drivers used in the KUBIK system Connecting a KUBIK XTRA is done via the special connector in the bottom of the KUBIK FREE. The 6 wire connector cable transfer the signal to the woofer and tweeter module individually utilizing the active crossover in the KUBIK FREE, and power the indicator LED for easy access to a visual status check of the KUBIK system