10 Micron Pleated Polyester Sediment Filter 4.5 x 20 Polyester Pleated Cartridges are manufactured from durable polyester to provide you with a superior pleated filter that is washable, reusable and durable. Filters are chemical and bacteria resistant, have a great dirt holding capacity and extend the time between filter changes. Polyester Pleated Cartridges are suitable for a variety of uses and can be used in residential, commercial and industrial applications. The media is pleated around a polypropylene core for added strength and the ends are immersed in a thermo setting 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.