The API Nexx Extension is an extension for the Nexx External Filter. The extension includes a connection kit and filter media. The API Rena Nexx Extension gives not only filtration but also flexibility in your filter. Add one extension to increase filter capacity up to a 400 litre aquarium, or add two extensions to increase capacity to a 600 litre aquarium. The pump is adjustable and does not need to be updated. TheRena Nexx Extension is a module filter that grows with your interest and allows you to add to the API Nexx Filter through a clip connect for increased filtration. As you increase your tank size, add more fish or simply want to exercise your options you can add extension modules. Quick and easy 3 steps for media replacements in 4 minutes or less Flexible filtration options Superior water quality with the proven results of Bio-Chem Zorb Size 4 cartridge Includes all necessary equipment to easily increase the capacity of your Nexx filter in minutes.