TOPHORT 8 Inch 700 CFM Inline Duct Fan with Variable Speed Controller - HVAC Ventilation Blower for Grow Tents, Hydroponics & Home Ventilation Systems

It is great I use it at work I work in a steel shop that gets super hot in the sumer and it puts out 3 times the air as a regular fan and I can.put it on a work bench by the door and ot pulls the hot air out making the shop 30 degrees coolerThis thing moves air! I use it for a pellet stove during the winter to bring the heat upstairs and it works great! Now I'm using it to move the cooler air from the basement to the upstairs. Works great.A little noisy but, it's a fan mounted in the rafters under a hardwood floor. To be expected. Don't really understand why people would complain about a fan that makes noise. IT'S A FAN! It has moving parts and unless this is in a shed or a garage or somewhere not attached to the house, then you're gunna get some noise. This fan moves a ton of air and the variable fan speed is a super bonus! I can regulate the amount of heat/cool air that I want to come upstairs while keeping the basement cozy!We replaced a much smaller duct fan with this product and were happy to report the dramatic increase in air volume moved. We live in a rural home with the basement heated by a fireplace, so sought a way to move some of the heat to the upper living area.We probably got 3x to 4x the volume of warm air from the fireplace, through the overhead duct and out the floor duct. But the fan was so powerful that it set up a vibration on the floor allowing us to 'dial down' the rpms and eliminate the vibration and still get great air volume.I recently had a couple walls taken down in my home and the original rectanglular vents were inside the wall. The contactor rerouted it using 6 inch tubing which significantly reduced air flow to my 2nd floor to almost nothing. Needless to say it felt like a sauna up there. Bought 2 of these(for the two that had been rerouted and a temperature control module to turn them off and on based on temperature. Like night and day. The powerful boosters had my upstairs feeling like a fridge. 5 stars!Bought both a 6" and 4" from the same maker. The 6" puts out a high volume of air but is NOT very adjustable with the variable speed controller. The difference between maximum and minimum air flow on the rheostat controller is almost no difference, as compared to the 4", where the controller goes from high flow to almost no flow. The 4" is much more controllable and is what I expected in a rotary controller. The 6" is not what I had hoped for but seeing that the box got recycled, I can't send it back now.I like this fan. It is not too loud and continously works. The only issue I have had is keeping the duct secure to the outlet. The finish is so smooth that the duct comes off occasionally.This fan does exactly what it supposed to. I also paired it with a timer outlet switch and what a dream. I use it with a carbon filter for a space of 6feet by 5 feet by 9 feet tall. In a such a small space the fan and filter combo exchanges the air with in really fast so I'm happy about that.This little thing moves some air, however, the vibration level is unacceptable. It’s not very loud, except that you can hear the vibrations throughout the whole house. I’m using it to move warm air from the wood stove room, to my bedroom. It is accomplishing this task, just sounds annoying and you can feel the floor vibrating if you stand above where it is mounted in the basement.