Low flow pumps manufactured by Micropump Inc. include centrifugal pumps, ten series of external gear pumps, micro-annular gear pumps, and valveless piston pumps. The centrifugal pumps are available with a flow rate ranging from 1.5 L/min to 27 L/min and with maximum differential pressure of 20 psi. The external gear pumps have flow rates from 8.5 mL/min to 42.9L/min, and the micro-annular gear pumps are available with flow rates from 0.003 mL/min to 1152 mL/min. Designed for highly viscous fluids, the valveless piston pumps feature flow rates of 5 mL/min to 940 mL/min and maximum differential pressure of 100 psi.