Trigger at the 1st and 4th valve slide, intonation ring at the 3rd slide.
The mass of the 4th valve looks volume-strengthening and substance-strengthening. Ideally for the Haydn's concert.
The combination of heavy screw caps and the english rim at the bell cause a very good center and separation of the tones.
The enlargement to the E, D and C trumpet has the advantage that the musician holds the usually same instrument in hands in 4 different tunings. For the E tuning (Hummel-Concert) are changed leadpipe and slides, the bell of the Eb trumpet remains.
For the baroque or classical D tuning are changed the bell and slides. It is used either the bell of Eb or the C version.