[package includes] 1 double sponge filter with 2 containers + 1 bacteria ball bag + suction cup. The filter must be used with an air pump and a 4mm air hose. Note: Pump and air hose are not included. Please choose a strong enough air pump according to your fish tank size. [easy to use] Just use a 4mm air hose, with an air pump connected to one end and a filter connected to the other. Place it above or below the water line. [Removable fine sponge] You can easily remove 2 sponges from the filter to clean or replace it. Both sponges are thin, which means beneficial bacteria have a larger surface area to survive. Do not wash the sponge with tap water, just rinse or squeeze the sponge with aquarium water. [dimensions] 175 mm wide, 40 - 80 mm long, 50 mm sponge filter [multi - filtration function] the aquarium filter combines biological filtration, oxidation and physical filtration. The sponge can capture larger particles of debris and clean water without catching small fish. Ceramic biofilters help remove harmful substances and provide extra cleanliness to allow your fish or shrimp to live a healthy life.