Impedance: 6/8/12 Ohm Coil Diameter: Φ25.4mm 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℃