Compatibility: This filter is compatible with stainless steel 67oz/2L and 108oz/3L pet fountains. Also compatible with cat fountains - check product images for compatibility. Filter: pet water fountain filter aids in water purification and odor elimination, providing healthy and pure water, protecting your pet's drinking water. Note: Soak and rinse the cat water fountain filter with clean water before use. Clean the filter every time you change the cat fountain water. Replace filter and sponge every 2-4 weeks Color: As Shown Material: Activated carbon + cotton Package Contents: 16 * cat fountain replacement filters 16 * pre-filter sponges Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.