I did not buy the duct brush to clean dryer ducts, but to clean pine straw
out of rain gutter covers on my house. I put the brush and 3 of the extensions
in a 1/2 inch copper pipe(to keep the extensions straight-not wobbling)
and hook a portable drill to it to spin the brush while standing on the ground
holding the brush over the inlet of the gutter covers where the drain water
flows thru and into the gutters. Pine straw from trees around my house drop
onto the roof and is washed by rain into the gutter covers and blocks rain
from entering the gutters. Works great!!!