Types of Trumpets
The trumpet family
B♭, piston valve trumpet is by far the most popular trumpet and the one most players begin learning how to play trumpet on. Like all brass instruments however, the B♭ trumpet is part of a whole family of trumpets ranging from the tiny Piccolo Trumpet, which is half the length of a B♭ trumpet to the big Bass Trumpet which is twice as long as the normal B♭ instrument. Some trumpets use the long, thin piston valves (like the B♭ trumpet) and others short, round rotary valves but they all do the same job, adding tubing.
Most trumpets other than the standard B♭ are generally used in classical music, sometimes because of their unique sounds and sometimes for historical reasons reaching back to the days before valves were invented.