Cartridges are produced with genuine Reemay filter media and durable polyurethane end caps. Prevents harmful bacteria from growing on the cartridge. Less bacteria results in a reduction of foul odors, algae, black mold and other harmful contaminants which foul a cartridge. Antimicrobial protection lasts as long as the cartridge itself. Easier to clean than any other filter. 100 percent polyester core for strength and durability.