Zensor is very robust.
Jeff,
Out of sheer habit, I found myself 'hitting' windows shut with it; on three-or-four occasions and the pole was fine; no problems.
And then I started to get more confident and cheeky with it and found I could put a fair amount of pressure on the pole to scrub bird poo.
I may buy another; I think Matt said that the bottom two sections would fit onto the Zensor giving me another 6 foot of height, which is enough to do the highest windows I currently do.
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The only thing about it that I don't like is that I work from an estate, and my old Ungers used to sit nicely on the roof rack, but with these poles I have to put them in the car; and the long section goes over the seats into the driving area.
Can you see what I mean about my Unger poles on top of my car's roof rack?