21 speaker system series bose acoustimass surface matt colour white transmission mode cable front speakercentresurround connection to subwoofer number of speakers 3 components 2x front 1x subwoofer impedance 4 8 ohm front speaker build type satellite speaker front speaker types magnetically shielded wall mountable dimensions front wxhxd 83 2 x 95 5 x 84 9 mm front weight 054 kg front connector panel clamp contacts centre connector panel clamp c