Did someone on here explain how to adapt it?
Yes, it literally takes two minutes. Buy one of Scrimmy's Harris pole adapters (under a tenner and will last for years and years), discard the top couple of fishing pole sections and hacksaw a section of the third pole so that it slips nicely into the fishing pole.
I just use the same brush for my Harris, it just slips over the end of that too; so if I want to clean ground floor, I just slip it off the Harris and onto the top section of my fishing pole and bob's yer uncle, a nice ground floor pole and you're not carting two poles or brush heads about.
It does mean you have external pole hose, but this has advantages as well as disadvantages; and I'm fine with it.