Image Dynamics ID4 50W RMS 4" ID Series Full Range Coaxial System with 20mm Silk Tweeter - Pair 4" ID Series Full Range Coaxial Car Speakers | Power Handling: RMS: 100 watts per pair / 50 watts each Recommended Power Range: 5 - 50 watts RMS per channel | Mica-polymer composite woofer cone Butyl Rubber surround | 20mm Silk Dome Tweeter | Y-35 Magnet Motor Structure Top-mount Depth: 1.90" | 4 ohms impedance Frequency Response: 100-22,000 Hz | Sensitivity: 87dB