Product review (2 stars): Thar she blows, or down with this periscope...
I purchased this periscope vent to install as a part of the dryer exhaust cleaning project.  I wanted to replace the flexible vent because I thought that this smooth vent will prevent lint buildup as well as let me move the dryer closer to the wall and make the laundry area look neater.

From the first time I saw this product I was wondering how this adjustable periscope vent could be made airtight to prevent dryer exhaust from escaping.  Well, it is not.  I adjusted and installed it according to the instructions, and then ran the dryer.  I moved my hand along the vent and felt hot dryer exhaust blowing from every gap. This issue was encountered by at least one other reviewer - Melissa D. Felthousen: "we had to pull the unit out and tape the seams of the periscope".  Aside from the obvious drawbacks of venting warm humid air into your laundry room, I believe clothes dryer exhaust contains carbon monoxide, and I do not want to pump it into my home.

After this first test I wish I could return the periscope vent but I have already cut pieces of it that were interfering with the gas line connection, so, I decided to make it work.  I removed the periscope and used&nbsp;<a data-hook="product-link-linked" class="a-link-normal" href="/Nashua-324A-Cold-Weather-Premium-Foil-Tape-2-1-2-in-x-60-yds-Silver/dp/B0015V93KG/ref=cm_cr_arp_d_rvw_txt?ie=UTF8">Nashua 324A Cold Weather Premium Foil Tape: 2-1/2 in. x 60 yds. (Silver)</a>&nbsp;to tape all gaps.  I reinstalled the vent and tried it again, but still I could feel dryer exhaust blowing around the areas where round fittings connect to the periscope vent's flat surfaces.  I removed the vent again and taped those seams too, which was more work than I wanted to do.  I think it is OK now, but in my opinion it is absolutely not worth the money or work.  Besides the vent not being airtight, I found the periscope's fitting that connects to the wall vent to be too short, I had to struggle with it to stay securely in the wall.

At the end of the project my dryer is closer to the wall, but I don't think any gain in space and neatness was worth the struggle.  Prior to installing this vent, my dryer was farther away from the wall than the washer, but now the dryer is closer to the wall than the hoses in the back allow me to move the washer, so the fronts of the two can't be aligned.

I realize that this type of vent may be the only option for some people but, if space permits, I would recommend considering alternative ways of running the regular tubular vent.  Looking back, I believe I should have used a couple of 90 degree fittings and a short piece of the tubular vent, it would have made the installation quick and simple with no taping required.  I am rating the periscope vent two stars, because at the end it worked, but there were too many problems for me to like it.