The filter unit 3.0 is suitable for the Petkit Eversweet 2, Eversweet 2S, Eversweet 3, Eversweet Wireless, Eversweet 5 Mini, Eversweet Solo and Eversweet Solo 2 (Wireless) Pet Water Fountain. The 3rd generation filter has been extended by 150% of the filter material quantity. It is recommended to replace the filter every 2-4 weeks to ensure it works effectively. Otherwise, the effectiveness of the device will diminish. With the Petkit Fountain Filter you can ensure that your pets have constant access to fresh and clean water.