- Compatible: The size of the fountain filter is 12.7 x 12.7 x 1cm and the diameter of the center circle is 3.8cm. Measure your fountain and check before ordering if the filter can be installed in your fountain. 1. Compatible: The size of the fountain filter is 12.7 x 12.7 x 1cm and the diameter of the center circle is 3.8cm. Measure your fountain and check before ordering if the filter can be installed in your fountain. 1. Compatible: The size of the fountain filter is 12.7 x 12.7 x 1cm and the diameter of the center circle is 3.8cm. Measure your fountain and check before ordering if the filter can be installed in your fountain. 2. HIGH QUALITY MATERIAL: The replacement filter uses natural non-woven materials, coconut shell activated carbon and ion exchange resin. It can catch pet hair and dust, can effectively filter the dirt and remove bad odors in the water. 3. Easy to use: just put the raised side up and the flat side down, easy to install. Rinse the filter with water before