Aqueon EcoRenew Replacement Filter Cartridges are dual-sided, featuring fibers made from sustainable materials infused with carbon. This sustainable material allows these cartridges to be Eco-Friendly being both biodegradable and compostable. The EcoRenew cartridges also feature a NoDrip design to help eliminate extra water mess when changing your filter cartridges. Aqueon EcoRenew Replacement Cartridges are available in: Extra-Small, Small, and Medium. Due to the sustainable nature of the EcoRenew cartridge, it is recommended to replace BEFORE is starts to decompose-approximately 4 weeks.Made from sustainable fibers and infused with CarbonBiodegradable and compostableFeatures NoDrip design to help eliminate extra water mess when changing your filter cartridgesONLY for use with Aqueon QuietFlow Internal Power Filter with SmartClean Technology 5G3 filter cartridges included