S1 Series cartridges are manufactured from a pleated cellulose media and are designed for general water filtration purposes.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. Pleated design maximizes dirt holding capacity Designed for general water filtration purposes Recommended for chlorinated water supplies Economically priced