Each preassembled rite-size and emperor cartridge has a patented ribbed back that evenly distributes carbon for maximum wate. No bypass no tea bag effect. Contains: Emperor Filter Systems, Our Heavy Duty Emperor Filter Cartridge Delivers Two Full Ounces Of Activated Carbon Filtration And 45% More Mechanical Filter Area. Highest Grade Magnum Carbon Removes More Pollutants. Size/Quantity: 4 PACK