Marketing InformationPentair Pentek R series cartridges are manufactured from a durable, non-woven and reusable polyester fabric that is suitable for a wide range of filtration uses. The media is pleated around a polypropylene core for added strength. The pleated endcaps of-the standard cartridges are immersed in a thermo-setting vinyl plastisol. The big BLUE® cartridges have a molded end cap with gaskets. The pleated ends are sealed to the end cap with a thermoplastic adhesive. The overlap seam is sonically welded to reduce internal bypass improving filtration efficiency. The standard 9-3/4 in L cartridge has more than 4 sq-ft of polyester fabric, while the larger big BLUE® version has more than 16 sq-ft. The media is pleated to maximize dirt-holding capacity and extend the time period between changes or cleaning. R series cartridges are resistant to both bacteria and chemical attack making them suitable for a variety of residential, commercial and industrial applications.