Size: The size of the fountain filter is 12.7 x 12.7 x 1 cm, and the diameter of the center circle is 3.8 cm. Measure your fountain and check if the filter can be built into your fountain before ordering. (Attention: Does not fit “Catit” fountain.) High Quality: Replacement filter uses non- natural woven fabrics, coconut shell activated carbon and ion exchange resin. It can catch pet hair and dust, effectively filter dirt and remove bad odors in water. Easy to use: Just put the raised side up and the side flat down, easy to install. Rinse the filter with water before use. Tips: We recommend changing the replacement filter every 2-4 weeks to keep the water clean. pet drinking water and help your pets love drinking water. -12 Pieces Cat Water Fountain Filter.The internal material of the filter increased by 30%.The raised material can help improve the efficiency of filtered water. Extend life and provide pets with clean water. -Filters continuously clean and soften tap water to prevent