The MFJ-281 speaker is designed to reproduce the soft sound of sine waves naturally generated by the CW, making it easy to copy and highlight a communication fidelity you did not know existed. It has been carefully designed to improve speech intelligibility in the frequency range of 600 to 4000 Hz, while reducing unwanted, static and humming noise. The MFJ-281 amateur radio speaker features a high-end 3 "Mylar cone mounted in a well-designed speaker cabinet. It is covered with a thin metal grille that allows the sound to radiate without being choked. The included swivel mount lets you direct sound where you want it.