Model QD pump uses valveless piston technology. Single rotating and reciprocating ceramic piston accomplishes both pumping and valving functions, eliminating need for check valves and associated maintenance. Sapphire-hard internal ceramics insure that there is no degradation in accuracy over time and no need to recalibrate. Space-saving design measures 10 in. x 5 in. x 5 in., weighs only 10 lb, and can be wall mounted. Operates on less than 100 watts of power.