i have one 6'' sucking out the top, through the canfan canfilter 50. then i got this little squirrel cage fan from a friend. its mounted out side the window,on the windowsill, located directly behind the back wall. it sucks cool air and pushed through the inline lights. then next to that in the window I have a passive 6'' duct going to the bottom of my tent. although i may add another because my negative pressure still seems high. plus this was my first time to buy yoyo's and i must say they are everything their cracked up to be! best 10$ i ever spent lmao.