Alpine SWR-8D2 8" Subwoofer (2Ω + 2Ω) 8" Dual 2-Ohm Type-R Series Car Subwoofer Power Handling: Peak: 1000 watts RMS: 150-350 watts Impedance: Dual 2 ohms Reinforced Parabolic Cone Structure with Poly-Mica Dust Cap & Pulp-Kevlar Cone Durable HAMR Santoprene surround Nomex Progressive Conex spider Compound Radius Curve pole geometry Oversized 1.6", High-Temperature, 4-Layer Dual Voice Coil 52 oz. magnet motor structure Frequency response: 30-200 Hz Resonance Frequency (Fs): 40Hz Excursion: 12mm Top-mount depth: 4-1/2" Sensitivity: 83.5dB