Vents

Vents sits in a single category here, and within it in five families you should not mix up. The VK is centrifugal and the usual answer in a grow room. The TT and TT Pro are mixed-flow. The VKO is axial. The Quietline comes in an insulated housing. And the NK is not a fan at all but a duct heater.

Where the range sits

Everything from this brand is under Climate and Ventilation, in sizes from 100 to 250 mm and in U, R, Q and Duo versions per family. That page sets out at length how the families differ and when to pick which, including what the resistance of your filter and ducting does to the output. Start there if you are still choosing.