Our MP40 guard is designed with flow being the top priority. With a 15 degree adjustable flow pattern you will be able to maximize the flow in your aquarium by simulating a more gyre type flow pattern where flow can be directed up or around coral. With this method you can increase the power of your MP40's and move much more water throughout the aquarium without the risk of damaging coral tissue. It is not just a snap on cover but a full guard replacement which keeps it compact and efficient.