It’s the fretless instrument of the Brass Wind family. The length of the tube and its sounds change thanks to the slide bar named Kulis. The longer the tube is, the higher-pitched the sounds become. The shorter the tube is, the lower-pitched the sounds become. It was first used in the 15th century. They can be with a slide bar and piston. From high to low; Soprano, Alto, Piston Valve, Tenor, Bass and the Double Bass are the types of the Trombone. It is used in the Symphony, Opera and Musicals. The Trombone went into the West Classic Music Orchestra for the first time when it was used in the Fifth Symphony of Beethoven (deaf). The octave of its sound depends on its type and it is written with G, C, F clef considering its type.