Carbon replacement filters capture hair and debris remove impurities and odors and keep water fresh. Please Note: For Pet Fountain Only! Charcoal Filter: Premium Activated Carbon + Cotton Filters hair and residue to improve water quality. Made of high quality activated carbon and cotton material durable and reliable. Premium activated carbon filter for your daily needs. Compatible with Pet Flower Fountain. EASY TO USE: Rinse the filter thoroughly with water before use and replace it every 2 to 4 weeks to keep the water fresh. ★Square★ Condition: 100% Brand New Material: activated carbon + cotton Package size: 13*8*13cm/ 5.12*3.15*5.12in Packing weight: 85g Gift Package ★Round shape★ Condition: 100% Brand New Material: activated carbon + cotton Package size: 13 *13*4cm/ 5.2 * 5.1*1.5in Packing weight: 80g Gift Package Packing list: 4* Cat fountain filter (optional) Notice: Please allow 1-3cm error due to manual measurement and make sure you don t mind before ordering.