I'm looking for a carbon filter for my 8" inline exhaust fan which put's out 675 CFM's but I'm not sure what kind of carbon filter rating I should be looking at?

I found some priced at $150 that says 240 CFM's
Then another set $200 for 750 CFM's

For $50.00 I'm sure the 750 CFM's is probably the way to go ? But why? Any advice would be great.
DeeMar10 Reviewed by DeeMar10 on . Carbon Filter: How many CFM's ? I'm looking for a carbon filter for my 8" inline exhaust fan which put's out 675 CFM's but I'm not sure what kind of carbon filter rating I should be looking at? I found some priced at $150 that says 240 CFM's Then another set $200 for 750 CFM's For $50.00 I'm sure the 750 CFM's is probably the way to go ? But why? Any advice would be great. Rating: 5