Product review (4 stars): Good product, bad directions.
The directions are not clear, but the cleaning elements worked great.

The kit contains two of some of the smaller pieces that are necessary and easily lost.

The handle is not for winding and unwinding the flexible cable as some reviews suggest.  The handle rotates the cable to assist with snaking the cable past blockages.

My dryer has a 16 foot section between two 90 degree bends that hadn't been cleaned in thirty years.  I manually fed the cable from the outside and couldn't get past all the build up.  After cleaning and reattaching the inside venting to the dryer, I started the dryer and ran it while using the small 2" brush from the outside.  Large pieces of lint came loose.  I filled a plastic grocery bag with all the debris.  When I finished, no more lint was sticking to the cleaning head,  the cable banged metal on metal as I fished it in and out, and tumbling of the clothes in the dryer was heard through the now clean vent pipe outside.

A clear parts list and better directions are needed before this is a five star product.  The plastic housing and crank seem sturdy enough for home use, but only time will tell.