Product review (5 stars): Great space-saving invention, does what it's supposed to do.
Installation was a little difficult, due only to my very tight hole (not the item's fault). Once the piece in the wall is in place, you just position the other plastic piece onto the duct and twist into the wall piece. Done. We needed every inch we could get, and this was a definite space saver. If a house costs $100/sqft, this more than pays for itself.