Abstract: A radio receiver and a battery are housed in a button adapted to fit in the ear cavity. The button is attached to the ear by a hook. The radio receiver has an antenna tuned to intercept a single frequency radio signal, means for producing an audio signal from the radio signal intercepted by the antenna, and means for converting the audio signal to sound waves. The antenna comprises a coil wrapped around an insulated core made of compressed barium ferrite particles of controlled size and a capacitor in parallel with the coil. Due to the high effective permeability of the barium ferrite core, a sufficiently narrow band width and signal strength for satisfactory radio reception in the A.M. broadcast band can be obtained with very small core dimensions.