This cartridge is the key to the multiplication of a diverse microbial rich solution from your Vermi T 5/10 Extractor. The new Vermi T Bio-cartridge culture is contained in a 100% bio degradable coco fiber cartridge. This cartridge material not only reduces our impact on the earth, but also allows aerated water to fully penetrate the cartridge thus improving the microbial growth. The used Bio-cartridge can be buried in your garden, added as a great bio starter in a compost pile. If thrown away it will increase decomposition in our landfills.