Specifications: Free Air Resonance (Fs): 28.43 Hz Electrical "Q" (Qes): 0.715 Mechanical "Q" (Qms): 10.709 Total Speaker "Q" (Qts): 0.670 Equivalent Compliance (Vas): 2.530 cu. ft. / 71.64 liters One-Way, Linear Excursion (Xmax)*: 0.45 in. / 11.4 mm Reference Efficiency (no): 0.221% Efficiency (1W/1m)**: 85.64 dB SPL Effective Piston Area (Sd): 74.509 sq. in. / 0.0481 sq. m. DC Resistance (Re): 4.280 ohm Nominal Impedance (Znom): 4 ohm Thermal Power Handling (Pt): 300W Driver Displacement: 0.048 cu. ft. / 1.36 liters Approximate Dimensions: Nominal Diameter: 12.0" Overall Diameter (A): 12.52" Mounting Hole Diameter (B): 11.0625" Bolt Hole Circle (C): 11.7" Magnet Diameter (D): 5.05" Mounting Depth (E): 5.40"Approximate Weight: Unit: 8.11 lbs Shipping: 10 lbs