Need help picking a can filter

I have a 6inch 440cfm exhaust fan and i have no clue which out of all those numbers of can filters to use with it. Anybody out there know?

I bought the 6inch 440cfm fan/24inch carbon filter works great. here is a 6inch x 20 should do u good http://www.ebay.com/itm/4-6-8-Inch-Hydroponic-Carbon-Charcoal-Air-Filter-Odor-Control-Scrubber-CFM-/181015359476?pt=LH_DefaultDomain_0&var=480199500699&hash=item2a255b2ff4

Just going to throw this out there.. A good place to check would be the canfilters websites where they have the detailed specs including fan CFMs to match. I even gave you the links even though you should have googled this yourself.
http://www.canfilters.com/ | http://www.canfilters.nl/english/index.html