• The Customizable Cartridge for the BioStyle 20, 30, & 50 and BioStyle Thermo 30 & 50
• Add your own media – The BioStyle Customizable Cartridge allows you to optimize your BioStyle filtration by adding up to 120 mL of dry media to this cartridge
• Customizable – Add your choice or combination of dry, solid filter media into this empty cartridge based on your aquarium's needs; filter media sold separately
• Inner capacity is 120 mL with dimensions of 0.57 x 2.3 x 5.8 inches
• Contains one empty cartridge – Fits inside the filter chamber, in place of the 30 ppi filter foam, of the BioStyle filter. The quantity of cartridges that can fit in a BioStyle unit depends on the size of the filter.
• Changing the cartridge –  Timing to replace the cartridge depends on the media you put inside and depends upon aquarium size, number of fish and plants, and declines in filter performance
• Rinse cartridge with water before use. Cartridge can be reused.