They fit well but the sponge filter media is not as dense as the previous replacement filter I bought. I don't know how important this really is, but I do know that the denser the filter, the better it filters. Of course, a less dense filter can have more airflow, but I don't know if that's what I'm looking for in a filter. Edit: I just flushed this filter for the first time and can confirm my initial concerns; This filter media is much less dense than the previous replacement I bought. Afterβ¦