For 50 years, fishkeeping enthusiasts have looked to the Tetra name for products and solutions that add ease and beauty to their home. Whether you're an experienced hobbyist or just starting out, Tetra has everything you need–-from a large variety of quality fish food and innovative equipment to test kits and decor. Whisper Bio-Bag Cartridges complete the Whisper Power Filter package for a clean, easy-to-maintain aquarium. The Whisper Bio-Bag multi-packs come unassembled and offer economical pricing on larger quantities. Simply detach clip from Aerobic Frame and slide the filter bag over the frame. Add one packet of Ultra-activated carbon. Press the Aerobic Frame flaps down over the top of the filter bag and press the clip down over the flaps. Rinse under cool tap water to remove carbon dust. Insert the Bio-Bag into filter slots. For best results change the Bio-Bag monthly. GTIN:00046798261605. Free Shipping in the USA!