Self Cleaning Filter Media constantly moving around and rub against each other only letting the strongest nitrifying bacteria survive Simply Hook up to an Air Pump and getting all the benefits of oxygen in the water and a super charged biofilter. Oxygen Rich Water combined with strong nitrifying bacteria handle large amounts of ammonia and nitrite compare to other type of filter Easy to Remove Intake Sponge provides additional physical filtration Comes with Enough Media similar to K1 micro will float at first and start tumbling in a few days, Perfect filter to fill with any other media you might want.