25mm Mini resonant speaker full differ bone conduction loudspeaker water-resistant Parameter: Size:25mm Shape: Round Form of composition: Resonance Magnetic circuit type: Internal magnetic variety Frequency characteristics: Full frequency band (full range) Rated power: 3W Rated impedance: 4 ohms(If you wish 8ohms ,please touch me or depart me a message) Frequency response: 250Hz-20KHz (kHz) Directivity:positive Sensitivity: eighty three (dB/W) Sexual noise ratio: eighty three (dB) Harmonic distortion: five (TMD%) Package: 2pc