We have a 19 pound Maine Coon male cat.  Maine Coons' have many layers of fur and all different lengths.  The under pelt is so thick you can't part it enough to see the skin.  He is an inside cat but still gets his Advantage Purple once a month for prevention.  There are many dogs in the area that roam loose so fleas can come in from the dog activity outside.  I like the ability to apply Advantage topically and Oscar tolerates it very well.  I have read reviews where professional animal care providers say that Advantage is the best topical flea medication available.  We get it through Amazon for far less than what the vet charges plus it's delivered right to our door.  No more "out of my way" trips to the vet!...and complete flea control.