Cheminert Model M6 and M50 liquid handling pumps are a new generation of pumps for precision handling of liquids and/or gases, producing a bidirectional pulseless flow with a range of over six orders of magnitude. The M6 and M50 are positive displacement pumps, which means they are self-priming and tolerant of any gas which may find its way into the fluid lines. RS-232 and RS-485 communication protocols are incorporated into the microprocessor-driven controller. Software package controls flow rates, flow direction and metered volumes. Valco Instruments Co. Inc. Box 55603 Houston, TX, 77255