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: Mi105/108/110 (At Rated Voltage at 1M), Maximum Current: 700/1000/1200mA, Audio: Warble/1-Tone/6-Tone, Operating Temperature: -20～60℃