GROZ 45682 ¾Inch NPT Mechanical Fuel Meter (Gallon). 15-75 LPM (4-20 GPM) flow rate. Max 50 PSI working pressure. 14F to 150F working temperature range. For use with electric fuel pumps or gravity flow applications (min. gravity head of 4 feet). Nutating disc mechanism does not need a power supply and has +/-2% accuracy. Robust aluminum die-cast construction with high tolerance to fuel contamination or leaks. Easy user calibration. Rotate the register cap to every 90 degrees for easy display readout. With a 3-port design, use it inline or at 90 degrees inlet/outlet ports. With batch and cumulative total displays that show in gallons. Recommended for use with diesel, gasoline, and low to medium viscosity oils. Do not use water-based media.