The Seachem Algae Scraper Replacement Pads are a direct replacement for the pads used in the Seachem Algae Scraper. They fit in the removable scraper cartridge. The soft pads will wear and lose their shape over time with use, and in order to maintain effectiveness, they should be replaced regularly. These pads are ideal for use on soft algae deposits and use in acrylic aquariums where a metal blade is not appropriate. 3-Pack.