YFB-621 Tube in Fa
5th Valve Slide
![](/it/files/B983C070293E4A3D808AB472CF67226E_12074_240x110_ec9c2e162a37f3b51d0c2b8a235c869e.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".