ONLY Compatible with ORSDA® / Wopet 67oz/2L Stainless Steel Pet Water Fountain. If any doubt, please check product dimensions. Length is about 3 inch. Shortest Width is about 1 inch. Longest Width is about 1.35 inch. Thickness is about 0.25 inch. Triple Filtration System: Composed of a cotton layer, activated carbon and an ion exchange resin. Effectively to filter hair, heavy metals, keeps water fresh and improve the taste of the water. To prevent the activated carbon dust from shedding into water, please soak the cat fountain filter in water for 2 minutes then rinse thoroughly under running water before using. 3 days summer and 1 week in winter. If multiple cats are using the fountain, more frequent replacement will be necessary. 12-pack of premium pet fountain replacement filters and 6 Pack of pre-filter sponges individually packaged and sealed to maintain high quality. Enough supply for 1 to 3 months of use. Replace the pre-filter sponge every 2-3 weeks. Please feel free to contact us if you have any questions about our products, we'd like to help you!