I do hope that Nature's Miracle will eventually make an upgraded version of this box with smaller filter holes and on - top removal so those of us with «Will attack anything I notice» kitties can still use the filter. (chewy.com)
A group of small filter - feeding invertebrates had taken over on top of the heated panels, completely shifting the balance of the tiny test ecosystem. (discovermagazine.com)
Lymph nodes act as small filters that trap waste products in the lymphatic fluid and eliminate them from the body. (celluliteinvestigation.com)