Demand D9 Bookshelf Speaker (Black) PAIR. The step-up Demand D9 is the middle model and uses a 5.25 in polypropylene woofer that is augmented by a 5 in x 9 in racetrack oval-shaped passive radiator. This combination provides 88 dB/W/m sensitivity and a frequency response of 64 Hz to 22 kHz (+/-3 dB) with a total frequency response of 44 Hz to 24 kHz. Cabinet dimensions are 11.71 in (H) x 6.5 W) x 11.97 (D). This model can handle up to 150 watts of power.

Links:
Webpage