The Unger poles came with my trolley system from Peter Fogwill, and I have used them uyp to 4 stories high...they do bend a bit but they are fine.
I regularly use them for windows above conservatories, stupidly large porches (like todays house, it was almost a conservatory itself!)....windows above funny sticky out roof etc etc.
In some cases the bend is helpful as it can make it easier to reach hard to reach windows!!
Cheers
Steve