Leadpipe

Basic trombone anatomy

tuning slide counterweight mouthpiece slide lock ring bell knob/bumper water key/spit valve main slide second slide brace/stay first slide brace/stay bell lock nut

In a brass instrument, a leadpipe or mouthpipe is the pipe or tube into which the mouthpiece is placed.

For example, on the illustration of a trombone, the leadpipe would be between #3 and #4, the mouthpiece and the slide lock ring. In the illustration of a French horn, the leadpipe is #2.