Product review (3 stars): Not easy to install with zip ties...used duct tape!
I installed this baby recently (I've owned it for awhile; just sat here in the box).  I found that, as many reviewers have said, that the side entry points for the 4" dryer venting tubes are not a tight fit at all.  I tried to use the zip ties they provided (Uhh....guys, these are NOT clamps!) but they don't even go the entire distance around the 4" tube!  So, since I had the product basically jammed between the venting coming out of the dryer and the venting to the outside of the house, I just duct taped around the edges.  No zip ties required.

One thing I found out after the fact:  The little flapper in my unit was not attached.  Yup, didn't figure this out until I had the thing "installed".  So, I had to take it apart, reach in and snap it in place.  I did what someone else recommended - put a used dryer sheet behind the removable lint filter. I only had the thing on "open" a day or two then it got super hot here in the mid-west, so it's all venting outside now.

I look forward to a lint-free way to enjoy the heat I'm creating in the winter from my dryer.  I will update if things change; but you get what you pay for here.