[Wide Compatibility] Compatible with most 84oz/2.5L Square pet fountain on market. (Check shape and production dimensions). Compatible with Veken / Wonder Creature / Cosmart / NautyPaws / LAMYOO, etc... [Square Pet Filter] Diameter of hollow circle is about 1.3 inch. Length of square is about 4.92 inch. Thickness is about 0.4 inch. [Premium Quality Filters] Triple Filtration System: Composed of a cotton layer, activated carbon and an ion exchange resin. 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. 1 to 2 weeks in summer and 2 to 4 weeks in winter. If multiple cats are using the fountain, more frequent replacement will be necessary. [Premium 10 Pack Pet Fountain Filters] 10-pack of premium pet fountain replacement filters, individually packaged and sealed to maintain high quality. Enough supply for 2.5 to 10 months of use. [Friendly Customer Service] Please feel free to contact us if you have any questions about our products, we'd like to help you!