Aqueon Specialty Filter Pads are designed to address common water issues. The pads are pre-cut to fit in the Aqueon QuietFlow LED PRO Power Filter Bio-Media Grid. There are three varieties available in three sizes: Ammonia Reducing, Carbon, Phosphate Remover. Features: Pre-cut for easy installation For optimal performance, rinse first and replace approximately every 2 to 3 weeks 4 Count Carbon Pads remove pollutants and organic debris that discolor water, improving water clarity and reducing odor clarity and reducing odorFits Aqueon QuietFlow LED PRO Aquarium Power Filter 30 and 50 Includes: 4 Replacement Specialty Filter Pads Intended Pet(s): Fish Material(s): Carbon Product Dimensions: 4.00 X 0.50 X 0.50 Instructions: Pre-cut for easy installation. For optimal performance, rinse first and replace approximately every 2 to 3 weeks. 4 Count. For use with QuietFlow LED PRO Aquarium Power Filters 30 and 75. Aqueon QuietFlow Specialty Carbon Filter Pads, Size: 50 Gal | PetSmart