A 5ft unger no1 section instead of the brush handle, just drill a hole through both sections when exteded, then put a bolt through to stop it spining.
Also, if you get a second haris pole and take out the fist section, remove the plastic end cap off of the first pole and then inssert the second section from the second pole into the bottom and fix wiith a bolt.
This will give you an extender modular combo of about 30 ft
Hope that helps and make sense lol