What does the trombone use instead of a valve?

The Trombone uses a slide instead of a valve to change pitch. The slide allows the player to extend or shorten the length of the instrument's tubing, which alters the pitch produced. By moving the slide to different positions, trombonists can access various notes and create a smooth glissando effect. This mechanism distinguishes the trombone from other brass instruments that utilize valves for pitch alteration.