Quantum QB403 Beta Series 4-Inch 3-Way Speaker 4 Inch 3-Way Speaker, Piezzo Dome Tweeter , Mylar Dome Tweeter / Mid PP Cone, Ferric Oxide Magnet, Rubber Surround, Stamped Heavy Gauge Basket Max power: 120 Watts , RMS power: 40 Watts Sensitivity: 89dB Freq. response: 50Hz - 25KHz, Magnet size: 10 oz Ferric Oxide Magnet