Whisper Unassembled Bio-Bag Cartridge Medium (12 pack) Whisper Bio-Bag Cartridges complete the Whisper Power Filter package for a clean,
easy-to-maintain aquarium. Filled with Ultra-Activated carbon, the ready-to-use
disposable single packs remove waste particles, odors, and discoloration, and are easily
changed once a month. The Whisper Bio-Bag multi-packs come unassembled and
offer economical pricing on larger quantities.