My lances won’t fit in my AR110s, AR111s, AR112s, AR112s/t, or AR142s

With these machines, the first lance you attach to the spray gun MUST BE the smaller extension lance (PW4120400), as it is the only one that will fit directly into the spray gun.
Once the smaller extension is attached, any of the other attachments may be inserted into the end of it. You should keep this smaller extension attached as it will never have a need to be taken off.