This FCI carbon block filter cartridge, specific for DTS+ Mobile, removes any chlorine that might be present in the fresh water used to flush the watermaker when it is being shut down prior to a period of inactivity. Chlorine can damage the watermaker's membranes, and is present to some extent in virtually all dockside water. Fresh water flushing replaces saltwater within the watermaker - preventing possible corrosion of the internal parts, as well as reducing biological fouling of the membranes. This procedure is crucial to the longevity of the reverse osmosis membranes. With normal use, filter has 100 hours of life. FOR DTS+ MOBILE ONLY.