Features – High power 12” SPL subwoofer – Klippel® optimized – Efficient triple magnet – Massive aluminum cast basket – Reinforced paper cone – 3” copper voice coil – High-Roll sandwich surround – Double spider Technical data Model: GZHW 30SPL Diameter: 300 mm / 12″ Mounting diameter: 315 mm / 12.4“ Mounting depth: 198 mm / 7.8“ Voice coil: 75 mm / 3” copper voice coil Cone: Reinforced paper Power Handling: 3000 W SPL Power Impedance: 2 x 1 Ohm SPL: 85 dB Xmax: 45 mm / 1.77″ Fs: 35.4 Hz Qts: 0.44 Vas: 15.8 L / 0.56 cu.ft. Box recommendations : See owners manual.