Filter size is 5 x 5 inches, inner circle diameter is 1.45 inches. Compatible with pet fountain and fits any pet fountain. Other pet supplies in the same size, please check the size before purchasing. High quality activated carbon, enough for 6 to 60 minutes use. 12 months. Activated carbon and ion exchange resin to filter hair and dirt, remove odors and soften water for better tasting water. Recommended to replace every 2-4 weeks to keep the water clean and fresh. Rinse before use to prevent activated carbon powder from falling into the water.
