This ribbon-type media is sold in a roll, and will give your nitrifying bacteria 180 sq. ft. of surface area for colonization. It is suitable for 3 cubic ft. of filter volume. It is very light, yet is is virually indestructable. As you know, the more surface area available in a given space, the more nitrifiers you can grow in that space. Due to this product's durability and compaction qualities, you can get more surface area in a given space or filter. Compared to other types of media, such as lava rocks, it is far superior. Also it is very light in wieght, and much easier to clean and work with in general. It can be put in media bags or placed directly in the bio-filter. When combined with the proper quantity mat-type filters, your water will stay clear, and be able to grow enough nitrifiers to keep your water and fish healthy.