Tenor Trombone's Two Types

This wiry fella is playing a trombone.
Notice the large number of notes at his disposal!
The Italian word for trumpet is tromba.
So trombona means "large trumpet."
These names date back to the time before trumpets had valves.

Now they make trombones with three trumpet-like piston valves instead of a slide.
But much more common is a trombone with single rotary valve like that of a french horn.
Compare these King brand bones, without the "trigger" and with.

Here's a closeup of the extra tubing that the valve sends the air through.
The trigger is worked by the left thumb, so it doesn't interefere with normal operations.

But what good is this trigger, you ask?
The King trigger bone came with a little printed lesson.
The cover introduces the two purposes.

~ FURTHER READING ~

If you have a trombone, it is good to wash it periodically in warm water.
Extremely hot water is not recommended, as shrinkage may occur!