All a Dragonfly kit does is spray a small amount/ mist of pure onto the high level interior glass so what ever you do
don't buy one. (Total waste of money)
Buy a pad holder from Vikan plus pads (other pads are available so the choice will be up to your own preference) buy a pole adaptor, you can then use your exterior pole. (I think most of the window cleaning suppliers sell them)
What you do is spray a pad with pure and clean the glass using as little water as possible, you then take a dry pad and polish/dry
the glass, job done.