DROK15W Mini 3'' HiFi Full Range Speaker 4 Ohm Anti-magnetic Audio 2.0/2.1 Home Stereo Woofer Loudspeaker 90dB High Sensitivity for DIY Boombox Satellites Speaker Outer diameter: 78mm; Height: 52mm; Hole diameter: 71mm; Rated Power: 15W; Effective Frequency: 108Hz-20kHz. Adopts anti-magnetic design, effectively protect the surrounding electrical circuits and enhance the ability of anti-interference. 90dB high sensitivity, loud voice, good and clear sound quality with good bass, provide you a good hearing enjoyment. Uses blended bomb wave, strong fatigue resistance; imported rubber edge, prevent distortion. Ideal choice for DIY home computer audio stereo system .