Wide Compatibility: Compatible with Stainless Steel 67oz/2L, 101oz/3L and 108oz/3.2L & 4.0L/135oz Adjustable Water Flow Pet Fountain. Value Filter Set: Pack of 4 filters, pack of 4 pre-filter sponges. Triple Filtration System: Composed of a cotton layer, activated carbon. Effectively to filter hair, heavy metals ,keeps water fresh and improve the taste of the water. Keeping Health: Helps pet to increase water consumption. Note: Please rinse filter before use. Replace filter every 2-4 weeks.