It says this is for the KC I and II but...
It says this is for the KC I and II but the picture shows in on a KCIII. Whats up with that? Is it KCIII compatible or not?
No it only fits the KCI and KCII per Deuters website...
The KCIII comes with it built in (non-detachable) while this is an add on, it basically turns the KCII into the KCIII.