I would go with the Daytons...

Just because they've got more, um, 'history'.

The 4" duct, you can build your self... or get an Air Conditioner Contractor to build you a nice one with some sheet metal. The Active Air fans, to be quite honest, I'm trying a couple of pages I googled but I'm not getting anything. It's probably my piece-of-shit ISP. Anyways, I have a link to the dimensions of Dayton fans, if you want.

I'm not putting it here because I'm not in my computer.... but I'll check back later, and if you're interested, I'll post it.

I also have a link to other fans (the link is in the 10k Dream Grow Room setup thread) that seem kick-ass for these applications... forgot the name.

PS: Creator, can I please get your input (if any) on the 'fogger' system? http://boards.cannabis.com/showthread.php?t=40838 Thanks!
turtle420 Reviewed by turtle420 on . Better Exhaust Blowers? Active Air Or Dayton? Which exhaust blowers do you guys and gals prefer and why? See I personnaly like the higher static pressure of the dayton's but also like the built in in 4" duct mount on the active air's so I'm sort of torn on the issue. Rating: 5