The SunSun HW-504 A external aquarium filter is ideal for freshwater and saltwater aquariums with a water volume of up to 400 litres. The low-noise filter has a pump capacity of up to 800 litres per hour. Rubber feet ensure optimum vibration damping. It can be placed under or next to the tank to save space. The hose connections on the top of the lid can be rotated through 360° for optimum positioning. The scope of delivery includes filter media for 4 filter stages. The filter baskets with practical handles can be filled individually with the filter material. Please note that the filter materials are sorted from coarse to fine: 1st stage: mechanical filtration (e.g. filter fleece). 2nd stage: biological filtration (e.g. Bio Balls, ceramic rings); 3rd stage: chemical filtration (e.g. activated carbon, Phosphat-Ex); 4-stage filters can be extended by a mechanical or biological filter stage as required. Commissioning: Once the filter media have been inserted, the external filter is filled with water. To do this, simply press down the pump cylinder on the top of the external filter several times. The multifunction valve on the pump head has a quick-release coupling that allows the hoses to be disconnected from the filter container without having to empty them first. The multifunction valve can be used to regulate the flow and prevent the aquarium water from leaking.