Pentair OMNIFilter RS22 Heavy Duty cartridges are manufactured from a durable polypropylene string that is wound around a rigid polypropylene core. They are premium string wound solution to reduce fine sediment, including sand, silt, rust and scale particles. RS22 cartridges are wound in a precise pattern around the core, providing greater surface area. The result is higher dirt loading capacity and greater efficiency than standard wound cartridges. These string-wound cartridges are capable of withstanding temperatures up to 165°F, and will accommodate flow rates between 7 and  10 GPM with minimal pressure drop. The RS22 series cartridges are suitable for a wide variety of sediment filtration applications, including municipal and well water.