Aqua-Pure APS11701 Whole House - Replacement Cartridge Patent pending technology provides fine sediment filtration down to 5 micron "Rigid construction helps to eliminate sediment "unloading" due to variances in water pressure" Double open ended design allows for filtration regardless of which way it is installed in the housing The unique flow design of this cartridge allows for the use of finer, more effective granular activated carbon which yields a very low pressure drop Neoprene gaskets on both top and bottom help provide sealing in any housing, helping to prevent bypass of unfiltered water down-stream