Features: Most filters on the market; They are activated carbon. But our pet fountain filters are made to order. Made of high quality activated carbon, ion exchange resin and cotton mesh. The water is deeply purified and safer. High quality. Our filters are made from quality activated carbon. upper, ion exchange resin and high quality cotton mesh. Product details: compatible with the water source. 2.5L Square Cat Water. Filters Size: 4.92" x 1.3". It is compatible with water sources. MUDEELA / VEKEN / ISYOUNG /PARNER / HAPPYPAPA / DELOMO / BARVEST / LOETAD cat water and others of the same size. Ion exchange resin: softens tap water. Activated carbon eliminates odors, keeps water fresh. Cotton Mesh - Perfectly captures hair, sediment and dirt. Notes: Rinse filter thoroughly with water before use. Replace it every 2 to 4 weeks to maintain the freshness of the water. Replace more frequently with multiple pets using the source. A small amount of carbon dust may be released during the life