Impedance: 6/8/12 Ohm Coil diameter: Φ18.3mm Rated voltage: 12VDC/24VDC -- Only 15W Operating voltage range: 9～16VDC/20～25VDC Power: 15W/20W/25W Sound pressure/dB: 105/108/110 (At Rated Voltage at 1M) Maximum current: 700/1000/1200mA Audio: Warble/1-Tone/6-Tone Operating temperature: -10～40℃