Product review (5 stars): Nice concept and execution
I did a bedroom to laundry room conversion at my mother's house, and used as many items as I could to easily convert back to a bedroom when that day comes. This product was one of those items.
The collar that mounts to the wall fits snugly into the 4" vent pipe running outside. The inside collar had a bit of space to the aluminum flex pipe I used, but the clamp tightened nicely and everything fits together nicely.
I read a few comments that said the collars did not lock together and sometimes had to use screw to keep them secured. The ones I receive do click in and stay secure. Plus I put a little counterclockwise tension on the flex pipe so it would help keep it on.