Product review (3 stars): Saves space but leaks air
The periscope helped me regain six inches at least in my laundry room, entry area. It was not hard to install but you will need tin snips/aviation snips because as you move the periscope into position there will be extra metal that you must trim in order to make it fit. This is explained in the instructions but if you don't have a pair of snips then you will want to have them ready to install. The other install note is that the instructions will tell you that if the distance between the inlet and outlet is below a certain number of inches you will need to remove baffles from inside the periscope. I did not catch that note until after I installed the periscope. Fortunately my distance was greater that indicated in the book so I did not have to take the unit apart and redo.

My only real complaint is that the unit leaks a significant amount of air as the metal is bent into shape but not sealed. I used HVAC tape and sealed the gaps but I have had to reseal one area because the air being pushed out by the dryer blew the tape off one seam.

Overall the product gained me space but the amount of air/humidity leakage surprised me.