Value pack of 12 filters. Compatible with YOUTHINK, HOMMI, ISYOUNG, KOALAD, HAPPYPAPA, PEDY, automatic flower fountain and others of the same size. Size: 5in(outer diameter), 1.5in(inner diameter). Dual-action filters: Resin and active carbon. Resin can soften water and reduce the chance of lithiasis. Activated carbon can adsorb impurities and odor, keep the water fresh and clean. PP cotton outer layer can filter out hair, sediment and debris to keep water clean and fresh. Three types of filtration. Rinse the filter with water thoroughly before using, easy to install on pet water fountain.