21 pc speaker system stereo pc speaker colours brown wood shades transmission modes bluetooth cable wireless analogue input 35mm jack input line in analogue outputs 35mm phone jack bluetooth profile a2dp power rating 50 watt effective output 100 watt frequency response 20 20000 hz speaker system 21 system system active power supply mains connection nominal impedance 4 ohm suitable for smartphone tv mp3 player tablet game console desktop pc