The Pentair Pentek BBF1-20MB is a high-capacity Big Blue deionization cartridge engineered for facilities that demand ultra-pure water. Built with semiconductor-grade mixed bed DI resin, this 20" x 4.5" cartridge reduces dissolved ions to produce water up to 16 megohm resistivity, meeting the stringent purity requirements of pharmaceutical labs, medical facilities, cosmetics production, and electronics manufacturing. With a 1,850 grain capacity, the BBF1-20MB delivers significantly longer service life than standard 2.5" diameter DI cartridges, making it a cost-effective solution for high-demand environments. The low TOC resin minimizes organic contamination, while the polypropylene shell, endcaps, and integrated pre/post-filters provide durable, chemically compatible construction. Buna-N gaskets ensure a secure seal in any standard 20" Big Blue housing. Designed for a suggested flow rate of 1.25 gpm with a minimal 1.1 psi pressure drop, this cartridge maintains consistent output quality across operating temperatures of 40-100 degrees F (4.4-37.8 degrees C). Suitable for boiler makeup, cooling towers, humidification systems, laser equipment, and steam applications.