Rainfresh CF1 sediment filter cartridge is specifically designed for general household applications where filtration of sediment and particulate matter (dirt, rust, algae and more)is required. The CF1 filter cartridge is manufactured using a unique bead technology that results in a highly economical filter with excellent flow characteristics. The external surface is grooved to provide a higher surface area that results in better dirt holding characteristics and therefore, longer life of the cartridge.