Yield Lab4 Inch 190 CFM Air Duct Fan Vent System with Built-In Fan Speed Controller

Heavy duty, quiet. For my roll around AC, I use this on slowest speed because I extended the vent duct an extra 10’. I used a 6” to 4” duct adapter, since a 6 inch duct does not fit my window. Adequate ventilation. The bearings are so good it takes a while for the fan to stop after turning it off. Heavier than anticipated.

This fan is more powerful than expected and is a little noisy. I put a carbon filter on it and it cut the noise down a lot. Overall very happy with purchase maybe more fan than I needed for a 2x4 tent though.

The fan is being used to warm a greenhouse with heat from the ground and has run flawlessly 24-7 for the past month. It was just what I was looking for.

works like ad said, perfect...

Works really well