Description: Durable to use and easy to replace, suitable for all types of water. Effectively improve water quality. Cultivating the nitrifying bacteria, will give you superior biological filtration in your tank. This filter is noiseless and energy saving. These create numerous minute bubbles for increased oxygen flow. Simple and easy for filtering tank water, and keep tank water clean. S Size suits for the tank below 30cm height , L Size suits for the tank between 30-50cm height. Specification: Material: Plastic Filter S Size(DxT): Approx.8x3.2cm/3.15x1.26in Filter S Size(DxT): Approx.10.5x3.5cm/4.13x1.38in Sponge Filter S Size(DxT): Approx.7.5x1.3cm/2.95x0.51in,Hole Dia. Approx.2.5cm/0.98in Sponge Filter L Size(DxT): Approx.9.5x1.3cmcm/3.74x0.51in,Hole Dia. Approx.2.5cm/0.98in Package Includes: Filter S, Filter L Package: 1x Tank Filter Sponge Filter S,Sponge Filter L Package: 5x Tank Sponge Filter Note: Since the size above is measured by hand, the size of the actual item could be slightly different from the size above. Due to the lighting effects, monitor settings, etc. There could be some slight difference in the color of the pictures and the actual item.