What does George wear in his ear in the story, "Harrison Bergeron"?

George Bergeron, Harrison's father, wears a device that
makes noises in George's ears.  The purpose of the device is to prevent George from
being able to maintain thought for an extended period. George has been deemed smarter
than average, so he has to have a handicap that prevents him from using his
intelligence.  The radios that people like George have to wear are tuned to a government
transmitter that sends out noises about every 20 seconds. The ear radio makes sporadic
noises in George's ears disrupting his thought processes.  The story speaks to several
major themes, including mediocrity as the desired norm.  The people in the story's
society are all forced into sameness.  If they are better looking than average, they
must wear masks to hide their beauty.  If they are more graceful or athletic than
average, they wear weights to make them awkward. And if they are smarter than average,
like George and his son, Harrison, they must wear ear transmitters to keep them from
thinking and using their intelligence.