The CunoOCS retrofit cartridge upgrades the performance of existing competitive systems with the same premium performance and design characteristics as the Series 500 and 700. This is a graded density, multi-composite carbon block filter with 1 micron sediment reduction. The sanitary quick change design minimizes contamination of the filtration media, while the compact footprint allows the unit to be installed snugly behind the beverage unit or neatly under a cabinet. Maximum 1 year service life. 3.375-inch diameter x 11 3/8-inch long. Made in the USA.