light proof fans?

how would you do this on a pc case growbox, becuase it would need air holes...?

it might look weird but go to the plmbing section of a hardware store and get an abs 90 deg elbow (that fits around your fan of course)and put it on facing away from the light will reduce alot if not fully eliminate the light

I got a pc grow box light proofed. I can show you some pictures if you want. Theres a little in my grow journal, but not many closeups.