Each preassembled rite-sized and emperor cartridge has a patented ribbed back that evenly distributes carbon for maximum wat. Larger polyfiber filter pad traps more dirt. Faster. No assembly required. Highest Grade Magnum Carbon Removes More Pollutants. There s A Rite-Size Cartridge For Every Penquin Filter As Well As Other Filters. Our Heavy Duty Emperor Filter Cartridge Delivers Two Full Ounces Of Activated Carbon Filtration And 45% Mechanical. 1 PACK