YFB-621 F Tuben
5th Valve Slide
![](/de/files/B983C070293E4A3D808AB472CF67226E_12074_240x110_3676777d1c9152812203a43362fed119.jpg)
A 5th valve slide extension supplied with the YFB-621/621S allows you to change between "longer half step down" or "longer whole steps down".
A 5th valve slide extension supplied with the YFB-621/621S allows you to change between "longer half step down" or "longer whole steps down".