High Quality Driver PD04T:
Throat diameter: 1" (25mm)
Mounting type: screw on 1-3/8"
Nominal impedance: 8 ohms
Power rating: 500watts RMS
Sensitivity:  113 dB
Frequency response:1.2k-18kHz
Recommended crossover:2.2kHz or higher(12dB/oct.minimum)
Diaphragm material: titanium
Voice coil: 1.75"(44.4mm) ,polyimide film,CCAW winding
Magnet weight:25 oz (ferrite)