CerMedia MarinePure Block Bio-Filter Media for Marine and Freshwater Aquariums， 8 by 8 by 4-Inch</br></br><div style="text-align:left"><b>[Product Information]</b><br><ul><li>Ceramic Bio-filter Media with Vast Surface Area AND Open-Flow Porosity</li><li>Nitrate Reduction</li><li>Ammonia and Nitrate Removal</li><li>Lighter and more effective than Live Rock</li><li>Inert Ceramic</li></ul></div></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br><img src='http://ecx.images-amazon.com/images/I/41DUWp9alYL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/61eIcUGhNAL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/51MXIh14kRL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/51vWhqh3t-L.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/41u5UoSQM4L.jpg' noproxy></br>