Fento Original InlayEnsures the correct distribution of pressure across the knee and lower leg, which prevents knee and back complaints Once the inlay of your FENTO MAX has become worn after repeated use and no longer offers the right ergonomics, you need only replace this inlay rather than the whole knee protector. This breathable inlay was specially developed for the FENTO MAX and is the secret behind the ergonomics of this specific knee protector.