For information on aftermarket silencing rings and other ways to make your HHKB quieter, see Silencing.
The introduction of the Happy Hacking Professional 2 Type-S brought a slightly-modified slider design combined with silencing rings on each slider. These rings absorb the impact of the slider when it makes contact with the housing after being pressed and returning to the unpressed position.
The following HHKB models have been released with built-in silencing rings, bearing the Type-S branding:
Currently, only the HHKB Professional Hybrid Type-S (and the limited 'Snow' edition) are available from PFU Fujitsu.