Official Tomxcute Replacment Filters - We recommend you using the official tomxcute replacement filters to match your tomxcute cat fountain, and more importantly to better protect your pets' drinking. Compatiable with Tomxcute BE-0004, PET-0004, PET-0007. Three-Layer Filtration System - The filter features a 3-layer filtration composition of cotton layer, activated carbon, and non-woven fabric, which keeps debris from contaminating the water and filters out any pet hair or food particles. Package Amount for 8 Months - We recommend you replacing the filters every 2 weeks, and meanwhile clean the fountain and the pump to extend service life. The 16+8 pack combination is for you can replace them regularly and enough for 8 months usage. Warm Tips - Please soak the filter in clean water for 5 minutes and rinse it thoroughly under running water before use. If you encounter any problem during use, please feel free to contact us, we will reply to you within 24 hours and provide you with a satisfactory solution.