jessops extension tube set

I notice jessops have extension tubes for pentax, they quote them as PENTAX 6x7 EXTENSION TUBE SET, does anyone have any knowledge of these and do they fit the K series?

This particular set fits the Pentax 67 camera, which is a medium format film camera taking 120/220 film.

These are far too big for the standard K bayonet mount.

Thanks John.I'll keep looking