The Tetra® Whisper® 20i Internal Filter for aquariums is the ultimate in quiet, convenient 3-stage filtration. This submersible filter mounts on the inside of the aquarium, rather than hanging from the outside, making it possible to place the tank flush against a wall and easily hide with tank décor. The air pump (included) provides bubbles that move water through the filter, efficiently filtering and oxygenating your aquarium. The water flows through Ultra-Activated® carbon, absorbing odors and discoloration, as well as through the dual-sided mesh of the Bio-Bag® Filter, trapping debris and fish waste. Filters up to 125 GPH while oxygenating water.The Tetra Whisper 20i Internal Filter adjusts easily to high or low water levels with a mounting clip. Each unit includes the filter, air pump, 2 feet of airline tubing and one medium Tetra Whisper Bio-Bag Filter cartridge (change monthly – replacement small filter cartridges available). For 10-20 gallon tanks.Since 1951, Tetra has developed the world’s most comprehensive body of fish food knowledge, and fishkeeping enthusiasts have looked to the brand 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. Highlights: UNIVERSAL DESIGN: Tetra® Whisper® 20i Internal Filter is an all-in-one air pump and water filter system INTERNAL FILTER: Mounts on the inside of your aquarium with clip (included) CATCHES DEBRIS: Dense, dual-sided mesh filters debris and fish waste AERATES WATER: Air-driven design filters up to 125 GPH while oxygenating water CONVENIENT DESIGN: Uses large easy to change Bio-Bag cartridges; filter mounts inside aquarium, making it possible to place tank flush against the wall Specifications: Dimensions (Overall): 5.4 Inches (L), 9.88 Inches (H) x 4.9 Inches (W) Weight: 1.81 Pounds Intended Pet Type: Fish Pets subtype: Aquarium Filters Material: Plastic Care & Cleaning: Care Instructions Not Provided