Product review (4 stars): Much shorter drying time
Works fine. It does need a mounting apparatus fabricated in place because it is heavy and will not suspend on the vent piping alone. I made it from 2x4s and attached it to attic trusses as my vent is verticle and extends through the roof, approx 20 to 25' total. I was lucky enough to chose the correct wire for the automatic switch the first try. You will need a large box to set up the auto start switch. A wiring diagram would be helpful but someone with general electrical knowledge can set this up with no problem.

I cleaned about a 5 gallon bucket full of lint from the dryer vent before starting. This has substantially reduced drying time. I expect this to help keep the vent clean by keeping the vent dry and moving lint through faster.