L30 is a modern positive displacement pump for microchro-matography. L30 is the right answer on existing problems with flow rate stability. Its heart is a stainless steel preciselly polished cylinder having volume 30 ml. A piston with front PTFE sealing is moving in the cylinder. Piston drive is secured by special ball screw which is connected to the gearbox and step motor. Pump cylinder has independent temperature control and thus flow pulses due temperarure changes are excluded. Mechanical part is situated in pump box in horizontal position and pump cylinder is slightly inclined to serure that all air bubbles leave lightly the cylinder. Flow rate (1 ul/min – 2000 ul/min) and its linear change in time can be set well as an interval of pump action. The suction (full cylinder within 1,5 min) can be adjusted to be done either manually or automatically when pump stop the action.