BOSE RMS218 VLF-subwoofer is design primarily to extend the low-frequency response of Bose RoomMatch arrays down to 25 Hz. It features dual Bose LF18 18-inch high-excursion woofers. Frequency Response (+/-3 dB) : 30 Hz - 200 Hz Frequency Range (-10 dB) : 25 Hz - 250 Hz Nominal Coverage Pattern (H x V) : Omni-directional below 100 Hz Crossover Frequency : 60 - 100 Hz (active, external DSP) Dimensions : 21" x 37" x 41.5" (534 mm x 940 mm x 1055 mm)