The French horn is a brass instrument made of about 12–13 feet (3.7–4.0 m) of tubing wrapped into a coil with a flared bell. The double horn in F/B♭ (technically a variety of German horn) is the horn most often used by players in professional orchestras and bands. A musician who plays any kind of horn is generally referred to as a horn player. In informal use, "horn" can refer to nearly any wind instrument with a flared exit for the sound.
Components of the french horn
Mouthpiece: On brass instruments the mouthpiece is the part of the instrument placed on the player's lips. The mouthpiece is a simple circular opening that leads, via a semi-spherical or conical cavity, to the main body of the instrument.
Valves: Valves are used to change the length of tubing of a brass instrument allowing the player to reach the notes of various harmonic series. Each valve pressed diverts the air stream through additional tubing, individually or in conjunction with other valves.
Water Key: A water key is a valve or tap used to allow the drainage of accumulated fluid, consisting of condensed breath moisture, from musical instruments.