Wide Compatibility - PewinGo, Aerb, Omasi, Bonve, Pedy, DADYPET, Parner... our fountain filter fits most 2-2.5 liter cat fountains Dimensions: outer diameter 125mm, inner diameter 37mm, thickness 10mm Better Filtration - Activated Carbon + Ion Exchange Resin. Expel debris, absorb heavy metals, eliminate odors. Protect your little cat from unnecessary infections. Give them healthier, tastier water juice Rinse and Face Up - Rinse the fountain filter for 10 minutes before use to remove charcoal dust. Please put the flat front side up to ensure the best filtration 2-4 week change - Although our fountain filter can last a long time, to ensure the best protective filtration for our pets, we suggest a change every 2 to 4 weeks. With individual packaging, each fountain filter can be easily stored and well reserved with the best effect