Filters help prevent clogging of spray heads and ensure optimum performance. Inserted below the spray nozzle, they keep debris from plugging up your sprinklers, and are essential for proper functioning of the radius adjustment screw. Filters can be cleaned and reused, but sometimes they get too clogged, lost, or otherwise damaged. Replacing a filter is as simple as removing the existing nozzle and filter, inserting the new filter, and reinstalling the nozzle. For outdoor irrigation use with cold water only.