200W Rms 4 Ohm Paper Cone Woofer Pro Audio 15 Inch General Specifications: Nominal Diameter: 15 inch. Rated Lmpedance: 4Ohms. Operating Bandwidth: 50 to 2.5KHz (-3dB). Power Handling Capacity: 250W RMS. Sensitivity (1W/M): 98 dB(3dB). Voice Coil Diameter: 3 inch. Thiele-Small Parameters: Resonance Frequency Fs: 32.49Hz. DC Resistance Re: 3.4Ohms. Mechanical Q Factor Qms: 3.0845. Electrical Q Factor Qes: 0.5591. Total Q Factor Qts: 0.4733. Equivalent Cas air load Vas: 322.23 L. Surface Area of Cone Sd: 0.084 m2. Efficiency Bandwidth Product EBP 58. Voice Coil Over Hang X-max 6.0 mm. Physical Information: Cutout: 13.38".