This parallel double-plunger model provides superior performance at micro flow rates, and enables stable delivery over a wide range of flow rates, from 0.0001 to 3.0000 mL/min (with a maximum operating pressure of 130 MPa) or from 3.001 to 5.000 mL/min (with a maximum operating pressure of 80 MPa). Its ultrahigh-pressure capacity allows using long columns packed with micro particles. It smoothly tracks settings and provides precise solvent delivery even for programs with sudden changes in concentrations, which is desirable for ultrafast gradient chromatography.