20" x 2.5" 30 Micron Polypropylene Construction NSF 42 Certified PX30-20 Purtrex replacement water filter cartridges are genuine OE parts, made in the USA, that will capture and hold dirt and sediment as small as 30 micron in size. Built to provide maximum performance at an exceptional price point, these cartridges are made from 100% Polypropylene and meet all requirements set forth by the FDA for safe food and beverage contact.