[Compatibility] PETSTANDARD Replacement Filter Compatible with Whisker City Water Fountain. These are PET STANDARD branded filters. [Premium 10 Pack Pet Fountain Filters] Pack of 10 Filters [Compatible Pet Filter] Filter Measurements: 2.75" x 1.75" x 0.25" [Premium Quality Filters] Double Filtration System: Composed of a cotton layer and activated carbon. Effectively to filter hair, heavy metals, keeps water fresh and improve the taste of the water. [Frequency Of Replacement] To prevent the activated carbon dust from shedding into water, please soak the cat fountain filter in water for 2 minutes then rinse thoroughly under running water before using. Change every 1 to 2 weeks in summer and 2 to 4 weeks in winter. If multiple pets are using the fountain, more frequent replacement will be necessary. PETSTANDARD Replacement Filter for Use with Whisker City Water Fountain. These are PET STANDARD-branded filters. Pack of 10 filters. Filter measurements: Approximately 2.75" x 1.75" x 0.25". Features a double filtration system with a cotton layer and activated carbon. To reduce carbon dust, soak the filter in water for 2 minutes and rinse thoroughly under running water before use. Recommended replacement: Every 1 to 2 weeks in summer, and every 2 to 4 weeks in winter.