15" Woofer, Realistic Mach One, Mach Two, W-1500 Original Realistic (Radio Shack) Optimus Mach One, Mach Two woofer design Size: 15-1/4 Specs: Impedance: 8 ohms, Re: 7.2 ohms, Power: 125 watts RMS, 250 watts max, Response: 22-1200 Hz, Sensitivity: 90 dB, 1 watt, 1 meter, Le: 1.82 mH, Fs: 22 Hz, Vas: 12.09 cu. ft., Qms: 4.94, Qes: .63, Qts: .56, Xmax: 3.5mm Factory AUTHORIZED service and parts. SUPERIOR quality, LARGEST selection, and the BEST prices!