Product review (3 stars): Not that great of a dryer vent kit. Cheap construction.
I bought this to put a dryer vent in a house that had brick exterior. I used a 4 inch coring bit to make the hole and the cheap tin pipe that came with this kit fit ok, but the outside louver piece fits OVER the 4 inch pipe, so it's actually like 4 3/8" diameter if you wanted to get the louver piece flush with the brick. In my case, I couldn't really make the hole larger than 4 inches, so I had to cut and install pieces made from firring strips to trim it out. Essentially without the trim, the louver plate stuck out from the brick almost an inch.

My opinion is it should have clearly stated that the actual needed hole size was 4 3/8". Or made the louver plate to fit INSIDE the 4 inch pipe. I have to believe there are better kits out there.