Product review (4 stars): Worked fine but felt a little cheap
Works fine once you trim this with tin snips.  Also, I recommend you use aluminum tape on all corners for a tight seal.  Without it, you will gat leaks all over the place given the one size fits all design.  The secret is, put the tape on after fit up but before installing.  It's hard to put the tape on (except for the connector pipe) after the fact.