Product review (5 stars): Great product
My dryer is on 2nd floor and is vented down and out of the basement. It is approximately 40 ft long with at least 3 90's and corrugated pipe. My wife was very frustrated with the time it took to dry everything. Even if I bought a new dryer I needed to make a change in my venting. I researched several boosters and decided to try this product. the hardest part of the installation was connecting to the corrugated pipe which was barely protruding out of my 2nd floor laundry room. I stood the booster up right behind the dryer. I did clean out my vent before installing the booster to make sure it was clean. I had previously done this a couple of months ago too. I turned on the dryer and had to reach down and feel the booster to make sure it was running. I agree with another reviewer that it would be nice if it had a small light on it to let you know that it was on. I then went outside to check the volume of air coming out of the vent.  air flow was doubled,at least. I put in a full load of towels and set it for an hour. It was previously taking 2 hours at least to dry. After one hour the full load was dry. Our drying time on everything has been cut by 50 to 70 percent. I am very satisfied as long as the unit keeps working. we've only had it for 3 weeks.