High quality 2.5”x10” pleated polyester filter cartridge to ensure the best possible protection of the high pressure pump and membranes. Filters should be replaced with new, so it is recommended to have a stock of spare filters handy for any voyage. These filters are used on all Ventura series, Cape Horn, Catalina, Newport series, and the Aquifer Series as well as older models such as the Spectra 180C, 200C, and 380C systems.