Product review (3 stars): Has trouble with 90 degree bends
The brush does a good in cleaning the aluminum dryer duct.  The bristles are fairly soft and pick up the lint nicely.  The extensions are probably to rigid for big bends in the duct.  I have a 90 degree bend about 2 to 3 feet inside the wall outlet.  The assembled handle will only push the brush part way through the bend, can't get it all the way around without fear of tearing the aluminum duct work.