Tetra Whisper Carbon Filter Cartridges complete the Whisper Power Filter package for a clean easy-to-maintain aquarium. The included ready-to-use disposable single packs of ultra-activated carbon remove waste particles odors and discoloration. Ready to use disposable filter packs Removes odor and discoloration With ultra-activated carbon Fits Whisper EX30 EX45 & EX70 Whisper Filter Cartridge multi-packs come unassembled and offer economical pricing on larger quantities. Carbon packs are easily changed once a month. It is recommended that you replace your Whisper Filter Cartridge when water begins to overflow excessively from the Wonder Tube chamber.