The Insider Internal Filter is an efficient internal filter for small tanks designed with innovative features that will keep your tank clear and clean. This functionally designed filter offers an easy to replace slide out floss and carbon cartridge. Another unique feature to the Insider is the hanger attachment. Not only will the hanger attachment fit under an aquarium hood and hold the Insider tightly in place, it also has the ability to adjust the height of the filter to allow for different water levels. All you need is a source of air to run this. Comes with an air stone inside as well.