DRIVER TYPE: imported Piezo. BODY DIAMETER: 4 inches. WATTS RMS.: 90. WATTS PEAK: 180. FREQUENCY RESPONSE: 1.5k to 22k Hz. SENSITIVITY (dB@1w/1m): 98. NOTE: This unit has a coil and 2 capacitors built in next to the ceramic driver to act as a crossover. Size 4.125" x 3.0". Weight 1.0 lb.