Pentek WPX50BB97P Fibrillated Polypropylene

http://www.waterfilters.net/WPX50BB97P-Fibrillated-Polypropylene-Water-Filters.html
The Pentek WPX50BB97P is a nominal 50 micron fibrillated polypropylene String-Wound sediment filter. These water filter cartridges are constructed of fibrillated polypropylene wound on a polypropylene core. They should be used when pressures require minimization of extractables and/or fiber migration. The WPX50BB97P water filters reduce sediment, sand, and silt.