Elite Carbon Cartridge for Hush 20 Power Aquarium Filter, 2-Pack Elite hush 20 pre-filtration pad polishes aquarium water while the activated carbon removes discoloration and odors The easy to use disposable cartridge should be replaced monthly Includes 2 cartridge per pack Measures 1-3/5-inch length by 4-4/5-inch width by 7-1/2-inch height This product weighs 0.40-pound