iSpring RO500 is the ultimate under-sink reverse osmosis system that overcomes all of the traditional RO drawbacks. With the flow rate of up to 0. 4 gallon per minute and up to 2: 1 pure water to waste water ratio, it is 4x more efficient compared to a traditional RO system. RO500's reinforced integrated water route design makes DIY installation a breeze. With a built-in boost pump and tankless design, the system can be easily fit and saves under sink space. The filter change indicator monitors each individual filter's life. Also, thanks to the tool-free twist and pull design, filter change can be performed easily without any water spill or leakage.