Boston Acoustics 110-001743-0 Single 7" Subwoofer Replacement for VRB Speaker (Certified Refurbished) Certified Refurbished product is tested & certified by Boston Acoustics to work like-new. The product includes all original accessories, and is backed by a 90 day warranty. Subwoofer Replacement for VRB compact bookshelf Speaker, Deep Channel Design MagnaGaurd magnetic shielding ensures the speakers magnetic field does not interfere with the televisions Frequency Response 48 - 20000 Hz, Recommended Amplifier Power 15 -150 Watts, Nominal Impedance 8 Ohm Sensitivity 92 dB, Crossover Frequency 2400Hz, Connectivity Technology wired