http://www.waterfilters.net/Pentek-P1-Sediment-Water-Filters.html<br />The Pentek P1 is a 1 micron spun bonded-polypropylene water filter cartridges designed to produce healthier, better-tasting drinking water. Manufactured from pure 100% polypropylene, the P1 is designed for purity and chemical compatibility. The spun fibers form a true gradient density from outer to inner surfaces and will not impart taste, odor or color to the liquid being filtered when used within the recommended temperature limit.<br />The P1's polypropylene construction provides superior chemical resistance and is not prone to bacterial attack. It can be used on chlorinated or non-chlorinated water supplies. The coreless strength of this water filter cartridge is achieved by sintering the many fibers into a solid matrix. It is tested and certified by NSF International to NSF/ANSI Standard 42 for material requirements only.
