This media bag will hold either lava rock or bio balls in the Bio Falls filters. This bag is for bio media such as bio balls or Lava Rock. This media bag will not work for pond carbon. Size 14x30 Biofalls Media Net ponddepot@msn.com Copyright - All World Rights Reserved Pond pumps, Pond Kits and Pondless Waterfall kits, Underwater Pond Lights. Aquaclearer Extreme bacteria and String Algae Buster and pond fish food. Pond Depot provides Do-it-yourself pond kits and Pondless waterfall kits delivered right to your home at great prices! Thank you for shopping at Pond Depot you online pond superstore!