Review on TerraBloom ECMF-150, Quiet 6" Inline Duct Fan With Variable Speed Controller – Ventilation Exhaust Fan For Heating Cooling Booster And Grow Tents by Kelsey Davis

I was surprised when I first took this fan out of this box. It was half the size of the vivosun 6-inch fan I was using. I looked inside the fan to find tiny 4-inch fan blades. I realize now this company is pulling some dubious business practices. They took a 4-inch fan and removed the ducting flanges. So they can sell it as a 6-inch fan for more money. If you look at other 6-inch inline fans like from vivosun they actually have 6-inch or larger fan blades.It is also spinning 2x the speed of the vivosun. Maybe it is to compensate for its smaller blades? But you can hear it trying it was turbo charged. If I lower the speed so the noise is the same as vivosuns then the air it moves feels noticeably weaker. The 350cfm is certainly a stretch. I have used fans rated at 200cfm that moves more air than this fan. Only positive thing is it has a nice metal casing and the speed control is works well.