The SP30-4520 4.5" x 20" 30 micron polyester pleated cartridges are manufactured from durable polyester to provide you with a superior pleated Filter that is washable, reusable and durable. This pleated filter is chemical and bacteria resistant with a great dirt holding capacity to extend the time between Filter changes. The SP30-4520 polyester pleated filter cartridge is suitable for a variety of uses and can be used in residential, commercial and industrial applications. The polyester media is pleated around a polypropylene core for added strength and the ends are immersed in a Thermosetting vinyl plastisol. Embedding and sealing each end of the Pleat in this fashion fuses the three components together forming a unified end cap and gasket. Specifications: 30 Microns. Bacteria Resistant. For City or Well Water Sediment Filtration Washable and Reusable. Made from Polyester. For use in Whole-house Filtration Systems MWH-D20-WELL, MWHSD20-WELL and any other for home or commercial.