SB ACOUSTICS SATORI, AT60NC-4 AMT RIBBON TWEETERFeatures Precision diaphragm assembly Unique foil damping Optimized rear chamber Two part faceplate Smooth controlled dispersion Very flat impedance curve Specs Nominal Impedance, 4 Ω DC resistance, Re 3.9 Ω Effective piston area, Sd 12.6 cm2 Free air resonance, Fs 2200 Hz Sensitivity (2.83 V / 1 m), 91 dB Frequency range, 2200-40000 Hz Net weight, 332 g