XINYOU XY-2892 Bio-Chemical Aquarium Sponge Filter High-quality aquarium sponge filter for efficient biological filtration Supports large bacterial populations to break down aquarium waste Dense, high-quality foam ensure reliable longer lasting aquarium use Operated by an air pump to create numerous minute bubbles to increase dissolved oxygen content Sponge dimension: 3.25"x 4 (h)" overall 3.25" x 9"(h)