 for your system. And I don't recommend just going out and buying the best one you can get because you can cause problems if you've got a higher MERV filter where you're looking at these filters and that's the filter rating. If you put in too big of a filter, you can actually cut down the airflow. So you want to make sure that the filter has the right airflow for your system. So don't always get the best one. The best one could cause some problems with your system and cause it to work harder than it should.