The trombone is a brass instrument, capable of producing a sound that is rich and brilliant, lower than the French horn but not as low as the sound produced by a tuba. The trombone's body includes a mouthpiece, first brace, second brace, slide, water key, tuning slide, and bell. Most brass instruments rely on valves to create varying pitches but the trombone relies on the slide. The slide replaces the valves in other brass instruments, which use valves to select tubing length. When the trombone player moves the slide out the note is lower and when the trombone player pulls the slide toward them the note is higher. The trombone is a predominantly cylindrical tube bent into an elongated "S" shape.