ITEM NAME:2pcs Speaker Horn 3W 4R 4cm Mini Amplifier Rubber Gasket Loudspeaker Trumpet BX Specifications: maximum diameter 4CM Magnet position 2.2CM Thickness 2CM Type: Electric (coil) use: Pa Shape: round composition: single Rated power: 3 (W) nominal impedance: 4 (Ohm) Frequency response: 170 (kHz) point: all Sensitivity: 100 (dB/W) noise ratio: 1 (dB) Harmonic distortion: 1 (TMD%).Magnet position 2.2CM. Type: Electric (coil) use: Pa. Sensitivity: 100 (dB/W) noise ratio: 1 (dB). Frequency response: 170 (kHz) point: all.