HQUA WF301 is a whole house water filtration system, 1” FNPT inlet/outlet, with the help of fittings included, could change to 1” NPT or 3/4” NPT inlet/outlet. Includes 3 Big Blue filters, 20”×5.5” each. First, Sediment Filter. Reduce dirt, rust, sand, silt, and other suspended solids. Second, Compound Filter. GAC+KDF, Reduce Heavy metals (Lead, mercury, copper, nickel, chromium), chlorine, odor, hydrogen sulfide. Final, Carbon Block Filter, Reduce certain heavy metals, and VOC's, chlorine, odor, color, and sediment. Bracket-mounted, No flow direction specified, Flow Rate: 3-15 GPM, Operating Pressure: 25-116 PSI. 180 days cartridge change suggestion. Or if you notice a drop on the pressure gauges, it indicates the cartridge has been blocking gradually. When the pressure dropped 10-15 PSI compared to the initial pressure that had been recorded on the maintenance log. It is the time to change the cartridges. Deluxe Accessories: Multiple pressure gauges included, Multiple timers included, Pressure relief valves and drain valves assembled on the filters, Long Housing Brush included, Different pipe fittings included, Maintenance Card included.