The Pentek WPX10BB97P is a nominal 10 micron Fibrillated Polypropylene String-Wound sediment filter. These water filter cartridges are constructed of fibrillated polypropylene wound on a polypropylene core. The fibrillated polypropylene should be used when pressures require minimization of extractables andor fiber migration. These water filters reduce sediment, sand, and silt.