Hawthorne Audio 15" OB "Augie", SI-OBA-15 15" low frequency augmentation driver Ideal for bass augmentation in open baffle and infinite baffle configurations Heavy cast basket Kevlar Reinforced Paper Cone Body w/mass plug Long excursion poly/cotton cloth surround Large copper shorting ring on the vented core Poly/cotton linear flat spider Knurled binding posts 2.5" voice coil Power handling: 225 watts RMS. Impedance: 8 Ohms SPL: 88.7 dB 1w/1m Le: 0.81 Re: 5.69 Ohms. Qt: 0.92 Vas: 250.3 liters Xmax: 7.15 mm Fs: 27.0 Hz Magnet weight: 67ounces Cut out 13.875" OD 15.25"