DS18 3" Compression Driver (Sold Each) Type: Bolt-on Titanium Compression Driver RMS Power: 400W MAX Power: 800W Sensitivity: 109dB Throat Diameter: 2" Voice Coil Size: 3" Impedance: 8 ohm Frequency Response: 500 Hz - 18.5 KHz Diaphragm Material: Titanium Magnet Material: Ferrite Magnet Weight: 65 oz Bolt Pattern: M6 Overall Diameter: 6.69"