Small double-head bio-sponge filters provide both mechanical and biological filtration. Simply install an airline into the unit and provide both aeration and filtration for your fish. Aerobic bacteria colonize the sponge providing a bacterial substance to facilitate the nitrogen cycle. In addition, the sponge traps larger waste particles. It mechanically cleans the water without trapping baby fish. These filters are useful as breeding filters, as a secondary filter or they can be used as a pre-filtration unit by fitting to an external or a top filter. IMPORTANT: These sponge filters require 3/16" aquarium tubing and either our DB-300 or DB-333 model pumps to function. Specifications: * Size: Small * Model #: AD-2831 * Product dimensions: 5.0″ (L) x 1.8″ (W) x 5.5″ (H) * Sponge dimensions: 1.8″ (D) x 3.0″ (H) * Max tank size: 10 gallon * Brand: JAJALE Includes: * 8 pieces of sponge filter (AD-2831)