3.Pro Audio good price, good quality Single 18" horn-loaded subwoofer Frequency Response(±3dB)35-250 HzFrequency Range(-10dB)30-300 HzSensitivity (1W/1M)105 dBMax.SPL131dB continuous,137 dB peakNominal Impedance8 ohmRMS Power Handling650 WPeak Power Handling2600 WRecommended Amplifiers600to1000 Watts into 8 ohmsEnclosure Dimension636(W)x956(H)x750(D)mm/25(W)x37.6(H)x29.5(D)inch Shipping Dimension676(W)x1006(H)x790(D)mm/26.6(W)x39.6(H)x31.1(D)inch LF Transducer1xHiPower L18/6620Net Weight71kg(156.5 lb)Shipping Weight79kg(174.2 lb)