【Compatible】This cat water fountain filter is compatible with a variety of cat fountains, the specific compatible fountain style, please check the product image list, before buying please confirm whether it is compatible with your cat fountain to avoid purchasing errors. 【Package】The package contains 8 cat fountain replacement filters and 8 pre-filter sponges. 【Filter】The cat fountain filter helps filter the water quality, while the pre-filter sponges blocks out any hair, dust or food debris. 【Note】Before use, soak and flush the cat water fountain filter with clean water,clean the filter every time you change the water of the cat fountain, and change the cat drinking fountain filter and sponge every 2-4 weeks.