The Flugelhorn is trumpet-like brass wind instrument with piston valves to change the length of the pipe, but with a wider, conical bore.
In the 1800s the Flugelhorn was used on the battlefield to summon the flanks of an army. Its sound is darker than a trumpet and used for a different type of sound to prevent soldiers from getting confused.
Like trumpets and cornets, the flugelhorn is constructed for the Bb pitch. Its mouthpiece is more conical mouthpiece than those of trumpets or cornets.
Source: Yamaha