Okay kiddo, have you ever seen a parade before? When there's a parade, sometimes you might hear some very loud instruments that help announce the arrival of important people or events. They're called "trumpets".
Now, the U.S. Army has a special group of trumpets that they use for really important events. They're called "herald" trumpets.
These trumpets are bigger than regular ones and they're made of shiny brass. They have a really special sound that carries really far, so people can hear them from very far away.
The people who play these trumpets are very important too. They're part of a special group called the "U.S. Army Herald Trumpets". They know how to play the trumpets really well and they have to practice a lot to make sure they're ready for any event.
These trumpets are used at lots of important events, like when the President of the United States visits somewhere, or when there's a big ceremony for the military. They help make the event really special and important.