light proof passive intake question

would 2 of these 4"x4" vents work as a passive intake? would they be light proof? i am using a 300cfm fan. GROWSPACE - 3.5FT X 2.5FT X 8FThigh

definatly work as passive intakes but so would any old hole, as for light proof, where u see this advertised? sometimes they actually say light proof.

try google light proof intake vents or sumet.

try this, this a very clever ideahttp://www.icmag.com/ic/showthread.php?t=135524

i could just run two 4" pvc pipes out of the grow room at a 90degree angle down. right?

I use dryer exhaust baffles on my growroom for intake. Just watch to see if they're hanging open at all if you see light escaping through them. Tape something to each baffle or just tape for some extra weight if they're hanging open. I'd say one is plenty actually.