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.protection lasts as long as the cartridge itself. Easier to clean than any other filter. 100 percent polyester core for strength and durability. Polyester Microban sheath for ease of maintenance. Extruded and reinforced PVC center cores. Embossed part numbers. Break-resistant bands. No pad adapters needed. Fits Rainbow Disposable Depth pool and spa filter. Features: High performance pleated polyester media Reinforcedend caps Extruded pvc center cores Break resistant bands Molded in threads, no loose inserts