This type of fan friend:
Amazon.com: MASSEY, NOW PMX, 4 inch Personal Fan, Gray/Silver: Kitchen & Dining

Walmart has this type of fan right now. Honestly I would advise anyone reading if you looking for a fan buy a few of these. There about 6 bucks right now. But there fan goes by a different name.

If you decide to buy another "inline fan" buy a 6 or 8 and use your other one as an active intake.
319 Reviewed by 319 on . lighting my tent with a 600w dual spectrum - Help i'm a 1st timer bought a tent kit that came with a 600 w (sunmaster dual spectrum) however even with my 5" fan and filter I'm running temps around 100f. should i buy a lower watt Metal halide bulb for the veg stage? then switch at flowering with the addition of another inlet fan to keep temps lower during the end stages? I've got the light approx 1 metre above my seedlings (running 18/6), they are stretching up (currently 2 - 3inches) and the 2nd set of leaves are showing through. Would appreciate Rating: 5