Gallonage and filter capacity monitor operates at flow rates between 0.01�0.5 GPM. Ultra low flow model. Accurately tracks the number of gallons of filtered water produced and alerts you when it�s time to change your filters. Also shows real-time flow rates. Displays in gallons or liters. For use with Stealth RO, Triton RO or any other systems with 1/4 in fittings and flow rates up to 1/2 GPM.