These replacement filter pads are made to slot directly into the bio-media grid of Aqueon QuietFlow LED PRO Power Filters, matching the filter size printed on the unit. Each pad is pre-cut so it drops into place without trimming, and the media inside is formulated to address a particular water quality issue such as excess waste, discoloration, or dissolved minerals. As water passes through the pad, it captures debris and interacts with the media layer to help maintain clearer, healthier aquarium conditions. Pads are intended to be rinsed before first use and are replaced on a regular schedule to keep performance consistent. They are built for freshwater and saltwater aquariums housing common pet fish. Only the filter model that matches the tank size listed should be used with a given pad.