What kind of handicap has been imposed on people with better than average mental capacity in the story, "Harrison Bergeron," by Kurt Vonnegut, Jr?

In ""
by , Jr., everyone has finally been made equal in every way. Nobody is smarter than anybody
else; nobody is more athletic or beautiful or anything. In this society, those who are naturally
better at anything have to wear some sort of handicap to even the playing field among the
citizens. A Handicapper General is in charge, and her agents go about their days making sure no
one is in violation of the policy.

People who are more intelligent than
average are required to wear a mental handicap radio in their ear.  Harrison's father, George,
has one of these devices. This earpiece connects to a transmitter from which the government
sends out a loud noise every twenty seconds. This is done so that people like George cannot
think about anything for very long.

"Every twenty
seconds or so, the transmitter would send out some sharp noise to keep people like George from
taking unfair advantage of their brains."

Harrison
is so highly intelligent that he is forced to wear large earphones and strong, blurry glasses
that give him terrible headaches and make him almost blind.