Five stage in line reverse osmosis RO filtration, quick change filter can be replaced easily, with pump, solenoid Valve, automatic valve, H/L pressure valve, flow limit. Cartridge: PP/GAC/PP/ RO membrane and T33C post carbon. Water tank option: KCTAS-2W(3.2G white), KCTAS-1(3.2G inner rubber balloon can be replaced), KCTAP-1W(4G plastic), KCTAS-2B(3.2G blue), KCTAS-2(2G) Capacity: 50/75/100GPD