SB ACOUSTICS SATORI MW19TX-4, 19cm TEXTREME CONE NEODYMIUM WOOFER 4OHMFeatures Advanced TeXtreme® cone Vented aerodynamic cast aluminium chassis Soft low damping rubber surround Advanced BIMAX spider Powerful optimized low distortion neodymium motor system Extended copper sleeve on pole piece Non-conducting fiberglass voice coil former Vented pole piece and voice coil Light weight CCAW voice coil Long life silver lead wires Specs Nominal Impedance 4 Ω DC resistance, Re 3.4 Ω Voice coil inductance, Le 0.14 mH Effective piston area, Sd 158 cm2 Voice coil diameter 39 mm Voice coil height 19.6 mm Air gap height 6 mm Linear coil travel (p-p) 13.6 mm Magnetic flux density 1.1 T Magnet weight 0.15 kg Net weight 1.46 kg Free air resonance, Fs 32 Hz Sensitivity (2.83V/1m) 93 dB Mechanical Q-factor, Qms 5.43 Electrical Q-factor, Qes 0.28 Total Q-factor, Qts 0.27 Moving mass incl. air,Mms 16.2 g Force factor, Bl 6.3 Tm Equivalent volume, Vas 53.2 liters Compliance, Cms 1.52 mm/N Mechanical loss, Rms 0.6 kg/s Rated power handling* 70 W * IEC 268-5, T/S parameters measured on drive units that are broken in.