Optos Electronic Metering Pumps Explore our line of electronic metering pumps with flow rates from 0.002 to 80 mL/min. at pressures to 6000 psi. Optos Electronic Metering Pumps » HP Manual Metering Pumps Explore our line of manual metering pumps with flow rates from .02 to 100 mL/min at pressures to 5000 psi. HP Manual Metering Pumps » VS Variable Speed Metering Pumps Explore our variable speed metering pump with flow rates from 12.0 to 144 mL/min at pressures to 5000 psi. VS Variable Speed Metering Pumps » Hydrolysis/Derivatization Explore our Hydrolysis/Derivatiation (H/D) WorkStation and spare parts for PicoTag Hydrolysis/Derivatization »