Philips Wireless Rear Audio module RWSS5510/00. Compatibility: HTS4561, HTS4562, HTS5540, HTS5550, HTS5560, HTS5561, HTS5562, HTS5580, HTS5581, HTS5582, HTS5590,..., Frequency range: 5.8 GHz. Power consumption (typical): 50 W, Power consumption (standby): 0.45 W, Power requirements: 100 - 240 V, 50/60 Hz. Weight: 2.43 lbs (1.1 kg), Dimensions (WxDxH): 4.96 x 4.96 x 5.16" (126 x 126 x 131 mm). Package dimensions (WxDxH): 8.5 x 6.85 x 7.09" (216 x 174 x 180 mm), Package weight: 3.86 lbs (1.75 kg). Total Harmonic Distortion (THD): 30%, RMS rated power: 250 W