Perfect Match: Compatible with various pet water dispensers, from 1.6L, 2.0L, 2.4L to 2.5L, flower fountain and others of the same size. Size: 5 (diameter), 3.6 (inner diameter) Please check your water dispenser card slot size before purchasing. High quality material: Our cat filter uses natural non-woven fabrics, activated coconut shell carbon and ion exchange resin. Triple Filtration: The outer cotton layer of each filter filters out large debris, hair and ruin. Triple filtration can ensure water quality, remove residual chlorine and odors, and remove heavy metal ions, providing cats with better fresh water. Easy to use: rinse the filter of the cat fountain before use to remove carbon dust. Then place the raised side up and the flat side down for easy installation. You will receive: 10 Cat Fountain Filters (Each Fountain Filter is individually packaged, you dont need so nothing to worry about). Replacement filters are recommended every 2-4 weeks to keep the water clean. Product Specification: Quantity: 10 Packs Outer Material: Square Natural Cloth Material the inner layer: coconut shell activated carbon and ion exchange resin Size: outer diameter 12.8cm, inner diameter 3.9cm, thickness 1cm