Product review (1 stars): DO NOT BUY!! A TOTAL WASTE OF MONEY - AMAZON SHOULD BE ASHAMED THAT THEY SELL THIS JUNK
I have never left a negative review for any product, but I had to for this one. This item is one of the most poorly constructed items I have ever seen. Tape is required over the entire unit due to very little spot welding and if you do not use tape air will escape. If you read the more positive reviews, you will find that the only way they were able to get this item to work was to make a lot of adjustments to it and use a lot of tape.  I finally gave up and used a regular vent duct.